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