Sec 23 Tumors and Hyperplasia of the Dermis and Subcutaneous Fat Flashcards
Heterogeneous group of mesenchymal neoplasm
Malignant fibrohistiocytic tumors
The diagnosis of fibrohistiocytic tumors is done principally on the basis
H and E-stained section
Represent the malignant end of a spectrum that begins with fibroplasias and benign fibrous tumors
Malignant fibrohistiocytic tumors of the dermis
Most common soft tissue tumor of advanced adulthood
Malignant fibrous histiocytoma (pleomorphic type)
Primary treatment of choice for “so-called malignant fibrohistiocytic tumors”
Surgery
Most common cutaneous sarcoma
Dermatofibrosarcoma protuberans
Can present at birth or in children but most patients are middle-aged adult characterized cytogenetically by a reciprocal translocation t(17;22) (q22;q13), or more frequently, a supernumerary ring chromosome composed of hybrid material derived from t(17;22)
Dermatofibrosarcoma protuberans
Encodes the β chain of the PDGF, a ligand for the cell- surface receptor tyrosine kinase PDGFR, which is a growth factor that acts as a potent mitogen for a variety of connective tissue cells
PDFGB gene
Slow-growing lesion that often presents on the trunk and proximal extremities; due to its indolent onset, the patient may present rather late when the tumor is already several centimeters in size; often misdiagnosed as a simple scar, keloid, or cyst
Dermatofibrosarcoma protuberans
Most common presentation is a firm, indurated plaque, often skin-colored with red–brown exophytic nodules
Dermatofibrosarcoma protuberans
The pigmented variant of DFSP
Bednar tumor
Considered the juvenile variant of DSFP, typically presents as a dermal or subcutaneous mass, which most frequently involves the trunk, thigh, or inguinal region
Giant cell fibroblastoma
Histopathology: dermal proliferation of monomorphous, slender, or slightly plump spindle cells with little pleomorphism arranged in a storiform pattern; epidermis is usually uninvolved; proliferation commonly infiltrates the subcutaneous fat along the fibrous septa, isolating adipocytes to form lucencies (“honeycomb” pattern)
Dermatofibrosarcoma protuberans
Histopathology: characterized by giant cells, irregular vascular-like space partially ligned by giant cells as well as myxoid to collagenous areas with elongated to stellated cells
Giant cell fibroblastoma
Very sensitive, although nonspecific, marker for DFSP
CD34
Most common site of metastasis in DFSP
Lung
Nodes
Standard management: DFSP
Complete local surgical resection with margins of 1-3 cm (recurrence rate: 13-52%)
Competitive antagonists of the adenosine triphosphate (ATP)-binding site, blocking the transfer of phosphate groups from ATP to tyrosine kinase residues of the substrates
Tyrosine Kinase Inhibitors: imatinib or nilotinib
Rare tumors that occur sporadically, can be associated with familial adenomatous polyposis (FAP), history of trauma or an operation; presents as slowly growing tumors that may arise from the muscular aponeuroses at any site of the body, but are most commonly found on the trunk and extremities which can be painless or minimally painful
Desmoid tumors, or Aggressive fibromatosis
Histopathology: monoclonal fibroblastic proliferation typically arising from muscular or aponeurotic structures but lacks nuclear and cytoplasmic features of malignancy; consist of spindle-shaped cells, separated by collagen fibers
Desmoid tumor
Rare, rapidly growing neoplasm of intermediate malignant potential which occurs mainly on sun-exposed skin (face, neck, and hands) of elderly individuals, presents as asymptomatic, solitary, often dome-shaped nodule, which may be eroded or ulcerated with sun-damaged skin
Atypical fibroxathoma
Represents a predisposing factor in the pathogenesis of AFX
Solar radiation
Histopathology: poorly circumscribed hypercellular tumor that may extend deeply into the reticular dermis; consists of an admixture of highly pleomorphic spindle, epithelioid (histiocyte-like), and multinucleated giant cells in the dermis; pronounced atypia, with bizarre, large, round, or ovoid hyperchromatic nuclei with numerous mitotic figures, large prominent eosinophilic nucleoli; and abundant, vacuolated cytoplasm
Atypical fibroxathoma
Useful markers in highly proliferative AFX
MIB-1 and Ki-67
Treatment: Atypical fibroxathoma
Surgery
Mohs micrographic surgery has less recurrence rate versus local excision
Represents a spectrum of malignant myxoid tumors of fibroblastic origin, presents as gradually enlarging painless dermal or subcutaneous mass on the extremities and limb girdles, but may also arise within the head and neck region, the trunk, hands, and feet
Myxofibrosarcoma
Most common malignant mesenchymal neoplasm of the extremities/limb girdles of older adults
Myxofibrosarcoma
Histopathology: characterized by variable amounts of hyaluronic acid-rich myxoid stroma, delicate blood vessels, and spindle- shaped or stellate fibroblasts
Myxofibrosarcoma
Histopathology: hypocellular tumors comprised of relatively uniformly appearing spindle or stellate cells dispersed within a myxoid matrix; while nuclear pleomorphism and hyperchromasia may be present, mitotic figures and other overtly malignant features are absent
Low grade Myxofibrosarcoma
Histopathology: characterized by hypercellularity, marked nuclear atypia, hemorrhage and necrosis, and a high mitotic rate
High grade Myxofibrosarcoma
Primary therapy for Myxofibrosarcoma
Local surgical resection (wide and deep) with 3 cm margins
Most common metastatic sites for Myxofibrosarcoma
Lung
Bones
Almost never a cutaneous tumor but involved as a result of direct extension or metastasis, found in the subcutaneous tissue
Undifferentiated Pleomorphic Sarcoma
Histopathology: spindle cells in a storiform pattern; stroma may be finely fibrillary, myxoid, or densely collagenous; bizarre epithelioid and giant cells may be present and may contain small amounts of lipid
Undifferentiated Pleomorphic Sarcoma
Relatively rare soft-tissue sarcoma of unknown histogenesis, presents as a painless, slow-growing, firm tumor often accompanied by superficial ulceration, hemorrhage, necrosis, and plaques; may grow to a large size, up to 20 cm in diameter
Epithelioid Sarcoma
Histopathology: characterized by marked cytologic atypia, frequent mitosis, vascular invasion, and absence of a granulomatous appearance; tumor cells are large epithelioid and may mimic a carcinoma; cells with a rhabdoid morphology can be seen
Proximal Epithelioid Sarcoma
Histopathology: nodules composed of relatively uniform polygonal cells, often with loss of cohesion, which merge in the periphery into spindle cells without demarcation; have relatively abundant deeply eosinophilic cytoplasm; mitotic figures are rare and only minimal pleomorphism is evident; stromal changes include desmoplasia with cords of bland spindle cells sometimes with storiform pattern; nodules frequently have central necrosis; hemorrhage is frequently observed
Classic Epithelioid Sarcoma
Treatment of choice: Epithelioid Sarcoma
Radical excision traditionally with clear margins
Chemotherapy for Metastatic Epithelioid Sarcoma
Doxorubicin
Ifosfamide
Most common benign tumors of childhood, occurring in approximately 4% of children by 1 year of age
Infantile hemangioma
Expressed in all stages of hemangioma maturation
GLUT1, a glucose transporter protein
Absence at birth or presence as a premonitory mark, usually an area of pallor, telangiectasias, or duskiness is characteristic
Infantile hemangioma
Always become apparent within the 1st month of life, period of most rapid growth typically occurs within the 1st 5 months of life, with 80% of growth being completed by 5 months of age
Infantile hemangioma
Most IH complete their course by the age
7-10 years old
Involve the upper dermis, with a bright strawberry red color
Superficial hemangiomas
Involving both super cial and deeper skin structures, have bright strawberry red color and skin color to blue in color
Mixed hemangiomas
Present as a localized, firm, rubbery subcutaneous mass that can be slightly raised with a bluish color or with telangiectasias involving the overlying skin, or may be deep enough that the overlying skin is completely flat and of normal hue
Deep Infantile Hemangioma
One of the most important factors affecting risk in Infantile Hemangioma
Anatomic location
A neurocutaneous syndrome that consists of the following features: posterior fossa brain malformations, segmental cervicofacial hemangioma, arterial anomalies, cardiac defects or coarctation of the aorta, eye anomalies, and sternal defects, such as sternal clefting or supraumbilical raphe
PHACE
Diagnosed PHACE syndrome
Facial hemangioma >5 cm in diameter +
1 major criterion or 2 minor criteria
Possible PHACE syndrome
Facial hemangioma >5 cm in diameter + 1 minor criterion or
Hemangioma of the neck or upper torso + 1 major criterion or 2 minor criteria or
No hemangioma + 2 major criteria
PHACE: Cerebrovascular
Major:
Anomaly of major cerebral arteries
-Dysplasia of the large cerebral arteries
-Arterial stenosis or occlusion with or without moyamoya collaterals
-Absence or moderate to severe hypoplasia of the large cerebral arteries
-Aberrant origin or course of the large cerebral arteries-
-Persistent trigeminal artery
-Saccular aneurysms of any cerebral arteries
Minor:
Persistent embryonic artery other than trigeminal artery
-Proatlantal intersegmental artery (types 1 and 2)
-Primitive hypoglossal artery
-Primitive otic artery
PHACE: Structural brain
Major:
Posterior fossa anomaly
Dandy-Walker complex or unilateral/bilateral cerebellar hypoplasia/dysplasia
Minor:
Enhancing extra-axial lesion with features consistent with intracranial hemangioma
-Midline anomaly
-Neuronal migration disorderd
PHACE: Cardiovascular
Major: Aortic arch anomaly -Coarctation of aorta dysplasia -Aneurysm Minor: Ventricular septal defect -Right aortic arch (double aortic arch) -Aberrant origin of the subclavian artery with or without a vascular ring
PHACE: Ocular
Major: Posterior segment abnormality -Persistent fetal vasculature (persistent hyperplastic primary vitreous) -Retinal vascular anomalies -Morning glory disc anomaly optic nerve hypoplasia -Peripapillary staphyloma -Coloboma Minor: Anterior segment abnormality Sclerocornea -Cataract -Coloboma -Microphthalmia
PHACE: Ventral or midline
Major: Sternal defect -Sternal cleft -Supraumbilical raphe -Sternal defects Minor: Hypopituitarism -Ectopic thyroid
Most common cardiac anomaly in PHACE
Coarctation of the aorta, most often involving the transverse aorta
Infants with periocular hemangiomas are at risk for these which if untreated, can lead to permanent visual loss
Anisometropia
Amblyopia
Segmental hemangiomas involving the preauricular, mandibular, chin, and neck skin which have a 60% risk of having symptomatic airway disease
“Beard area” hemangioma
Often present with the insidious onset of biphasic stridor between weeks 4 and 12 of life and are often mistakenly diagnosed as tracheomalacia, upper respiratory infection, or croup
Airway hemangiomas
PELVIS syndrome
Perineal hemangioma External genitlia malformations Lipomyelomeningocele Vesicorenal abnormalities Imperforate anus Skin tag
SACRAL syndrome
Spinal dysraphism Anogenital anomalies Cutaneous anomalies, Renal and urologic anomalies Associated with angioma of Lumbosacral localization
Infants with multifocal vascular tumors and extracutaneous disease
Diffuse neonatal hemangiomatosis
Most common extracutaneous site of Infantile Hemangioma
Liver
Rare complication in infants with massive hemangiomas of the liver
Hypothyroidism
Associated with Kasabach-Merritt phenomenon (KMP)
Kaposiform hemangioendothelioma (KHE) Tufted angioma (TA)
Most common complication of IH, occurring in approximately 15% of patients usually during the proliferative phase, occurs most frequently with segmental IH and at sites that are exposed to moisture and friction
Ulceration
Prognosis: Infantile Hemangioma
Excellent, with spontaneous involution and little to no sequelae
Were the first-line treatment for deforming, endangering, or life-threatening IH work best during the growth phase, causing slowing or cessation of growth in up to 90% of cases, with actual shrinkage in 1/3
Systemic corticosteroids
Associated risk: Facial, large segmental
PHACe syndrome (posterior fossa malformations, hemangiomas, arterial anomalies, cardiac defects, eye abnormalities, sternal clefting)
Associated risk: Nasal tip, ear, large facial (especially with prominent dermal component)
Permanent scarring, disfigurement
Associated risk: Periorbital and retrobulbar
Ocular axis occlusion, astigmatism, amblyopia, tear-duct occlusion
Associated risk: Segmental “beard area,” central neck
Airway hemangioma
Associated risk: Perioral
Ulceration, dis gurement, feeding difficulties
Associated risk: Segmental overlying lumbosacral spine
Tethered spinal cord, genitourinary anomalies
Associated risk: Perineal, axilla, neck, perioral
Ulceration
Associated risk: Multiple hemangiomas
Visceral involvement (especially liver, gastrointestinal tract)
Dosage of Prednisone for IH
2–3 mg/kg/day, typically for 4–8 weeks
Has replaced corticosteroids as the first line treatment for most deforming, endangering, or life-threatening IH
Propranolol
Dosage of Propronolol for IH
1.5 to 3 mg/kg/day given either 2 or 3 times per day for at least 6 months
Most concerning side effect of Propranolol which can be life threatening
Hypoglycemia
Side effects: Propranolol
Hypoglycemia Asymptomatic transient decrease in blood pressure Symptomatic bradycardia Agitation Sleep alteration Sweating Wheezing Cold hands
Mechanism of action of propranolol for hemangiomas
Vasoconstriction
Inhibition of angiogenesis
Induction of apoptosis
Side effects: Systemic corticosteroids
Diminished gain of height and weight Cushingoid facies (71%) Personality changes Gastric irritation Hypertension Immunosuppression
Side effects: Intralesional corticosteroids
Arterial embolization/injection
Atrophy
Systemic absorption
Side effects: Topical corticosteroids
Local atrophy
Systemic absorption
Side effects: Interferon-α
Spastic diplegia (neurotoxicity) Fever Hepatotoxicity Neutropenia Anemia
Side effects: Vincristine
Central line placement
Neuropathy
Abdominal pain
Constipation
Side effects: Laser
Pain Scarring Hypopigmentation Textural change Ulceration
Side effects: Surgery
General anesthesia
Scarring
Reserved for hemangiomas causing morbidity that are unresponsive to oral corticosteroids, or where such therapy is contraindicated
Interferon-α
Often used in the treatment of the KMP and its associated tumors, KHE and TA; Considered by some to be a second-line treatment for aggressive, complicated IH that do not respond to corticosteroids
Vincristine
Hemangiomas that are fully formed tumors at the time of birth and do not proliferate in postnatal life
Congenital hemangioma or Congenital nonprogressive hemangioma
Appears as a raised, violaceous tumor with large, radiating veins or with overlying telangiectasia and a halo of pallor; central ulceration may be present; most involute spontaneously by age 14 months, often sooner, and usually leave residual atrophic inelastic skin
Rapidly involuting congenital hemangioma (RICH)
Present at birth, but usually flatter, presenting as a well-circumscribed round to oval, slightly indurated, or raised soft-tissue mass with overlying telangiectasias and a rim of pallor
Non-involuting congenital hemangioma (NICH)
Benign vascular tumor that has also been called angioblastoma of Nakagawa; acquired early in childhood and have a protracted course; may present as a subtle stain-like area that later thickens, as a large, plaque-like, infiltrated, red or dusky blue-purple lesion, or as an exophytic, firm, violaceous, cutaneous nodule
Tufted angioma (TA)
Histopathology: tightly packed capillaries, randomly dispersed throughout the dermis in a typical “cannonball distribution” with crescentic spaces surrounding the vascular tufts, and lymphatic-like spaces within the tumor stroma
Tufted angioma (TA)
Rare vascular tumor that has usually been
reported in association with Kasabach-Merritt phenomenon which may be present at
birth or develop in early childhood as a brown-red stain at birth which begins to thicken and become purpuric, or as a plaque or nodule
Kaposiform hemangioendothelioma (KHE)
Histopathology: spindled cells with minimal atypia and infrequent mitoses lining slit-like or crescentic vessels containing hemosiderin
Kaposiform hemangioendothelioma (KHE)
Refers to the presence of platelet trapping in the setting of vascular tumors
Kasabach-Merritt phenomenon
Hallmark of KMP
Tender expanding vascular tumor with thrombocytopenia, usually severe
Rare condition, characterized by multiple cutaneous vascular papules and plaques that are usually present at birth with more developing over time; have intermittent thrombocytopenia and lesions in the gastrointestinal tract, leading to gastrointestinal bleeding
Multifocal lymphangioendotheliomatosis with thrombocytopenia (MLT) or Cutaneovisceral angiomatosis with thrombocytopenia
Rare vascular tumor most often seen with Maffucci syndrome which occur at any age and site but the extremities are the most commonly affected; locally aggressive
Spindle cell hemangioendothelioma
Histopathology: nodular, dense, spindle cell proliferation in association with dilated dysplastic veins
Spindle cell hemangioendothelioma
Rare condition characterized by ill-defined plaques with increased lanugo hair and sweating at the site of the lesion, usually located on the extremities or abdomen
Congenital eccrine angiomatous hamartoma
Histopathology: losely packed eccrine sweat glands associated with dilated capillaries, a few dysplastic venous channels, and a dense collagenous matrix
Congenital eccrine angiomatous hamartoma
One of the most common vascular tumors of
infants and children and can also occur in adults, (pregnant women) usually presents as a
solitary, red, rapidly growing papule or nodule, often
with a subtle collarette of scale with typical
locations include the cheek or forehead
Pyogenic granuloma or Lobular capillary hemangioma
Benign lesion presenting as a violaceous papule, often surrounded by a pale rim and peripheral ecchymotic halo, which fades with time usually on the trunk or extremities
Targetoid hemosiderotic hemangioma
Dermal nodule or a diffuse swelling on the head, neck, or extremities; low grade angiosarcoma
Endovascular papillary angioendothelioma (Dabska tumor)
Site of the most robust viral replication of HHV-8
Oropharynx
These tumors usually start on the skin as unilateral or bilateral bluish-red (hematoma-like) macules on the distal portions of the lower extremities which tend to progress slowly both horizontally and vertically and develop into firm plaques and, subsequently, into nodules common in Caucasian male in his sixties with a Mediterranean or Jewish background
Classic Kaposi’s Sarcoma
Occurs as nodular-, florid-, infiltrative-, and lymphadenopathic-types; with florid and infiltrative variants characterized by a more aggressive biologic behavior and lesions may extend deeply into the dermis, subcutis, muscle, and bone; lymphadenopathic type predominantly affects children and young adults with fulminant course with rapid progression
African endemic Kaposi’s Sarcoma
Observed predominantly in kidney allograft recipients, and patients receiving immunosuppressive therapy, most notably the treatment of autoimmune diseases; can occur as early as 1 month and as late as more than 10 years after transplantation
Kaposi’s Sarcoma in Therapeutically Immunosuppressed Patients
Early lesions that appear as small oval violaceous macules that develop rapidly into plaques and small nodules, usually on the face (nose, eyelids, ears, and on the trunk) where the lesions follow the relaxed skin tension lines may coalesce to form large plaques and have a tendency for rapid progression
AIDS-associated Kaposi’s Sarcoma
Aside from oral mucosa, KS lesions are most frequently found in
Lymph nodes
Gastrointestinal tract (stomach and duodenum)
Lungs
Histopathology: discrete increase in the number of dermal vessels, outlined by slightly irregular endothelial cells with vessels parallel to the skin surface, which are frequently slightly irregular and may form bizarre slits and clefts mainly located on the superficial dermis; focal hemosiderin deposits and extravasated erythrocytes and moderate inflammatory infiltrate can be found
Early patch-like Kaposi’s Sarcoma
Histopathology: extensive vascular proliferation at all levels of the dermis with multiple dilated and angulated vascular spaces dissecting the collagen and leaving a spongy network of collagen tissue
Kaposi’s Sarcoma plaques
Histopathology: presence of solid cords and fascicles of spindle cells arranged between the jagged vascular channels; biphasic angiomatous and solid tumor morphology changes to a clear-cut sarcomatous morphology with progression of the disease
Kaposi’s Sarcoma papules
Histopathology: consist predominantly of spindle cells arranged in bundles and interlacing fascicles and interspersed irregular slit-like vascular spaces without endothelial linings; advanced lesions may display pronounced pleomorphism, nuclear atypia, and mitotic figure
Kaposi’s Sarcoma nodules
Treatment: Localized Kaposi’s Sarcoma
Surgical excision
Cryotherapy
Topical 9-cis-retinoic acid
Radiation therapy
Treatment: Disseminated Kaposi’s Sarcoma (Internal Organ Involvement) - For patients with AIDS
Initiate highly active antiretroviral therapy (HAART)
Treatment: Disseminated Kaposi’s Sarcoma (Internal Organ Involvement) - For patients on immunosuppressive therapy
Reevaluate drug regimen
Treatment: Disseminated Kaposi’s Sarcoma (Internal Organ Involvement) - For AIDS patients not responding to HAART alone
Systemic cytotoxic chemotherapy
Liposomal anthracyclines (e.g., liposomal doxorubicin 20–40 mg/m2 every 2–4 weeks)
Paclitaxel (100 mg/m2 given every 2 weeks)
Treatment: Disseminated Kaposi’s Sarcoma (Internal Organ Involvement) - For patients with classical KS
Liposomal anthracyclines (e.g., liposomal doxorubicin 20–40 mg/m2 every 2–4 weeks)
Vinblastine (6 mg iV once a week) Doxorubicin/bleomycin/vincristine (20–30 mg/m2, or
10 mg/m2, or 1–2 mg every 2–4 weeks)
Interferon-α (3–30 million units daily three times a week)
Highly malignant vascular tumor presents as singular or multifocal “bruise”-like patches on the skin, most frequently on the face, the scalp, or the neck regions; upon progression, the lesions become violaceous, ill-defined spongy nodular tumors that bleed easily
Angiosarcoma
Angiosarcoma associated with chronic lymphedema most frequently, after mastectomy with lymph node dissection
Stewart-Treves syndrome
Histopathology: irregular, anastomosing vascular channels lined by endothelial cells with different degrees of atypia and mitotic activity; may alternate with areas of closely packed cells with a high mitotic index and sometimes spindle-like morphology
Angiosarcoma
Immunostains for Angiosarcoma
CD31 and CD34
Estimated 5-year survival for Angiosarcoma
15%
Treatment of choice for small tumors of Angiosarcoma
Excision with wide margins
Most common soft-tissue neoplasm
Lipoma
Presents as painless, slowly enlarging mass involving the subcutaneous tissue of the trunk, neck, or proximal extremities
Lipoma
AD disease caused by mutations in the PTEN gene with constellation of multiple lipomas, macrocephaly, lymphangiomas, and hemangiomas
Bannayan (Bannayan-Zonana) syndrome
Part of the spectrum of familial adenomatous polyposis and includes extracolonic manifestations such as desmoid bromatosis, osteomas, cysts, and lipomas
Gardner’s syndrome
Histopathology: circumscribed masses surrounded by a thin fibrous capsule composed of lobules of mature white adipose tissue divided by delicate and inconspicuous fibrous septa containing thin-walled capillary-sized vessels; adipocytes are univacuolated and mature with eccentrically placed, compressed nuclei
Lipoma
Lipomas with increased fibrous tissue are referred to as
Fibrolipoma
Characterized by the presence of conspicuous myxoid stroma
Myxolipomas
Characterized by a myxoid stromal background in addition to a proliferation of vessels of variable sizes
Angiomyxolipoma or Vascular myxolipoma
A lipoma containing metaplastic bone or cartilage within the tumor is referred to as
Osteolipoma (bone) or Chondrolipoma (cartilage)
Refers to the presence of intratumoral sweat ducts and sweat glands which may be cystically dilated
Cutaneous adenolipoma
Characterized by overgrowth of adipose tissue involving subcutaneous tissue and skeletal muscle of the trunk and extremities with osseous involvement usually in young children
Diffuse lipomatosis
Characterized by multiple symmetric masses composed of nonencapsulated adipose tissue with a predilection for the subcutaneous tissue and skeletal muscle of the neck, shoulder, and proximal upper limbs in adult males associated with increased alcohol intake
Benign symmetric lipomatosis (Madelung’s disease, multiple symmetric lipomatosis)
Characterized by a symmetric distribution of adipose tissue, giving rise to a “pseudoathletic” appearance
Type 1 Benign symmetric lipomatosis
Shows a more diffuse distribution, giving rise to a picture of more generalized obesity
Type 2 Benign symmetric lipomatosis
An unusual proliferation of adipose tissue involving the pelvis and retroperitoneal space, most common among black men in the third and fourth decades; urinary symptoms are frequent presenting signs, and the disease is associated with cystitis in 75% of cases
Pelvic lipomatosis
Rare sporadic disease typically affecting middle-aged women present with multiple painful subcutaneous lipomatous lesions frequently associated with other symptoms such as weakness, depression, confusion, lethargy, or dementia involves the arms and trunk but may be progressive to involve large parts of the body
Adiposis dolorosa (Dercum’s disease)
Rare tumor that affects infants and children and presents as a growing mass with a predilection for the hand
Histopathology: proliferation of adipose and fibrous tissue within the epineurium and perineurium
Lipomatosis of nerve (Fibrolipomatous hamartoma of nerve)
Rare entity that affects children and young adults which presents as papules and plaques with predilection for the buttocks, lumbar back, and posterior thighs
Histopathology: bands of mature adipose tissue in ltrate dermal collagen
Nevus lipomatosus superficialis
Relatively frequent and typically occur in young adults presents as a small nodule with predilection for the forearm followed by the trunk, upper arm, and legs associated with pain and tenderness
Angiolipoma
Histopathology: circumscribed and encapsulated; show an admixture of mature fat and capillary-sized small branching vessels in varying proportions
Angiolipoma
Well recognized but rare benign adipocyte tumor that shows a wide age distribution presents as painless, slowly enlarging tumor with predilection for areas in which brown fat can be found
Hibernoma
Histopathology: well-demarcated and lobulated
neoplasm with hallmark feature of its morphologic
resemblance to brown fat; tumors are composed of variable numbers of multivacuolated adipocytes with small, centrally placed nuclei and pale to eosinophilic and granular cytoplasm
Hibernoma
Neoplasm of adulthood with a peak incidence in the sixth decade with tumors typically presenting in deep soft tissue with a predilection for the thigh, followed by the retroperitoneum, groin, and paratesticular area as well as the mediastinum; enlarging painless mass is the typical presenting sign
Atypical lipomatous tumor or Well-differentiated liposarcoma
Histopathology: large, multilobulated, and most often circumscribed; composed of relatively mature-appearing adipocytes with marked variation in cell size; other findings include focal adipocyte atypia and the presence of hyperchromatic and often multinucleate bizarre stromal cells in cellular fibrous septa
Atypical lipomatous tumor
Represent approximately 10% of all soft-tissue sarcomas and are the second most frequent variant of liposarcoma; presents as large, painless mass with a predilection for the extremities
Myxoid liposarcoma
Histopathology: lobulated tumor composed of a mixture of bland-appearing oval mesenchymal cells without evidence of adipocyte differentiation and small univacuolated or bivacuolated lipoblasts, often with a signet-ring cell appearance
Myxoid liposarcoma
Subsets of Leiomyoma
- Solitary or multiple piloleiomyomas - from the arrector pili muscles
- Genital leiomyomas - from the mammillary, dartoic, or labial/vulvar muscles
- Angioleiomyomas - from vascular smooth muscle
Women with multiple piloleiomyomas may also develop uterine leiomyomas
Multiple cutaneous and uterine leiomyomatosis (also known as familial leiomyomatosis cutis et uteri or Reed syndrome)
Individual lesions range in size from several mm to 1 cm and are usually reddish-brown firm papulonodules that are fixed to the skin but freely moveable over underling deeper structures which can coalesce to form plaques or linear, grouped, or dermatomal patterns; extensor extremities, trunk, and sides of the face and neck are the most common locations; often have pain
Piloleiomyomas
Commonly present as solitary, deep papulonod- ules or occasionally, pedunculated papules on the scro- tum, vulva, penis, or areolar region; usually asymptomatic
Genital leiomyomas
Present most commonly as solitary, painful subcutaneous nodules on the legs in women that can grow to several cm in diameter
Angioleiomyomas
