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Histiocytoses Flashcards

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Dermatology Board Prep flashcards
1
Q

What is the progenitor cell for all histocytoses?

A

CD34

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2
Q

What are the groups of histiocytes?

A
  • Langerhans
  • Macrophage/mononuclear
  • Dendritic
    • Type 1: Papillary dermal dendrocytes, factor 13a positive
    • Type 2: Reticular dermal dendrocytes, CD34 positive
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3
Q

What is the gene identified in LCH and what percentage have it?

A

BRAFV600E

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4
Q

What are the 4 rough groups of LCH?

A

Letterer-Siwe
Congenital self-healing reticulohistiocytosis
Hand-Schuller-Christian
Eosinophilic granuloma

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5
Q

Clinical findings of Letterer-Siwe

A
  • <1 year of age
  • 1-2 mm pink papules, pustules or vesicles in scalp, flexural areas, neck, perineum, etc
  • Scale, crust and impetiginisation common findings
  • Coalesce and become tender –> cause fissures in intertriginous regions
  • Ddx: seborrheic dermatitis, diaper dermatitis, arthropod bites, varicella
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6
Q

Clinical findings of Hand-Schuller-Christian Disease

A
  • 2-6 years of age
  • Triad: diabetes insipidus (infiltration of posterior pituitary), bone lesions (80%) and exophthalmos
  • 30% have skin lesions –> when early they are more like Letterer-Siwe, when later become more like xanthomatous
  • You will have a hard time fixing the DI with radiation, but they can be treated with symptomatic vasopressin
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7
Q

Clinical findings of Eosinophilic Granuloma

A
  • localized variant
  • rarely have skin involvement
  • usually have an asymptomatic granulomatous lesion of the bone
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8
Q

Clinical features of Congenital self-healing reticulohistiocytosis

A
  • Limited to skin, rapidly self-healing
  • First few days of life
  • Characteristic wide-spread red to purplish brown papulonodules that have a nascular appearance
  • After several weeks the lesions crust and involute
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9
Q

Prognosis of LCH?

A

Association with malignancies - particularly haematological
Varies depending on sites involved
Those with CD34 progenitor cells with BRAFV600E mutation has a poorer prognosis

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10
Q

Immunostains for LCH

A
  • Positive for: S100, CD1a, Langerin (CD207) - then less done but: fascin, ATPase, peanut lectin, alpha-D-mannosidase
  • Negative: Factor 13a, CD68, CD163, HAM56
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11
Q

Histological findings of LCH

A
  • Epidermis:
    • May be come LCH cell infiltrate
    • Interface changes
  • Dermis:
    • LCH cell proliferation in the papillary dermis- these look like large cells with kidney shaped nuclei
    • Mixed cells: eosinophils, neutrophils, lymphocytes, mast cells, plasma cells
  • Secondary changes: haemorrhage, necrosis, crusting
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12
Q

Investigations for LCH

A
  • Biopsy first
  • Evaluate:
    • Haematological - FBC, blood smear, haem referral
    • Pulmonary - referral and CXR
    • Renal - urine, UEC
    • Skeletal - X-ray if suspicious
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13
Q

Treatment of LCH

A
  • Limited disease - skin only:
    • topical steroids, antibiotics, nitrogen mustard, imiquimod and NBUVB
  • Extensive cutaneous:
    • Case reports only: thalidomide, azathioprine, methotrexate
  • Reserve: BRAF inhibitor - vemurafenib, allogenic haematopoietic stem cell transplant
  • Multi-system: vinblastine + prednisone

When to use systemic treatment?

  • Multi-system LCH
  • Single-system LCH with multifocal bone lesions
  • Single system in special sites - i.e. vertebral
  • Single system with at risk CNS lesions
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14
Q

JXG Epidemiology

A
  • Very common non-LCH
  • M:F - 1.5:1
  • ?more common in Caucasian
  • rare in adults
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15
Q

JXG pathophysiology

A
  • suggested that is a histiocytic reaction to a traumatic or infectious stimulus
  • some suggest that generalised eruptive histiocytoma, benign cephalic histiocytosis and JXG may represent different expressions of the same disorder
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16
Q

JXG Cutaneous manifestations

A

Two forms:

  1. Small nodular/micronodular
    1. pink-red brown dome shaped papules, 2-5 mm in diameter
    2. widely scattered on upper body
    3. rapidly become yellow
  2. Large nodular
    1. solitary
    2. 1-2 cm in diameter
      • These 2 forms can coexist
      • Commonly head and neck, oral is rare
      • Prognosis:
        - limited to skin, self-limiting and benign
        - Regress within 3-6 years
        - Residual: hyperpigmentation, atrophy, anetoderma
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17
Q

JXG extra-cutaneous manifestations and associations

A
  • Extra-cutaneous:
    • Eye most commonly
      • usually unilateral
      • develops in <0.5% of patients with cutaneous lesions
      • occurs before 2 years of age, and often affects the iris
      • Hyphoema (haemorrhage into anterior chamber) and glaucoma can lead to blindness
    • Then lung
    • Other: visceral, bone, CNS (diabetes insipidus)
  • Associations:
    • CALMs
    • Juvenile monomyelocytic leukaemia
    • NF1
    • ‘Triple’ association: JXG, MM leukaemia and NF1
    • Other forms of leukaemia –> CLL, B cell lymphoma
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18
Q

JXG Histology

A
  • Well-demarcated, dense infiltrate of histiocytes within the superficial dermis in small lesions, in large lesions going to the subcutaneous fat
  • Loss of rete ridges
  • Mature lesions: Touton giant cells –> foamy xanthomatous appearnce
  • Scattered lymphocytes, eosinophils and plasma cells
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19
Q

JXG Immunostains

A
  • think non Langerhan:
    • HAM56
    • CD68
    • Factor 13a
    • Negative: CD1s, CD207 and sometimes S100
20
Q

JXG Treatment

A
  • No treatment required
  • Cosmetic –> remove
  • Ophthal review
  • If systemic:
    • Chemotherapy regimes
    • Radiotherapy
    • High dose systemic steroids
    • Cyclosporin
21
Q

NXG pathophysyiology

A
  • ?paraproteinaemia is primary inciting agent or a cofactor in eliciting a giant cell granulomatous reaction
  • normolipic plane xanthoma exist along a spectrum given both assocation to paraproteinaemia
22
Q

NXG Clinical

A
  • Multiple, asymptomatic indurated papules/nodules/plaques with a yellow hue
  • Peri-orbital region most common
  • 50% –> ophthalmic involvement: orbital mass, ectropion, ptosis, conjunctival lesions, keratitis, scleritis, uveitis
  • Paraproteinaemia - IgG monoclonal gammopathy in 70% of cases
  • Other findings: hepatosplenomegaly, raised inflammatory markers, lymphopaenia, low complement, underlying plasma cell dyscrasia i.e. multiple myeloma
  • Overall good survival - 100% at 10 years
23
Q

NXG Histology

A
  • Normal epidermis and superficial dermis
  • Palisading xanthogranuloma in mid-dermis to panniculus
  • Granulomas: histiocytes, foam cells, lymphoid follicles, plasma cells, giant cells with zones of necrobiosis
  • Cholesterol clefts
  • Both Touton giant cells and large, bizarre foreign body giant cells
  • Stains: positive for lysozyme, CD68 and CD11b (these are non LCH stains)
24
Q

NXG DDx

A
  • NLD
  • Normolipiemic plane xanthomas
  • Xanthelasma
  • Non-LCH disorders such as JXG
  • Foreign body granulomas
  • Sarcoidosis
25
Q

NXG Treatment

A
  • Treat underlying cause
  • Resolution or improvement of skin lesions seen in some treated with low dose chlorambucil, melphalan or cyclophosphamide
  • Surgical excision –>40% recurrence rate
26
Q

Indeterminate cell histiocytosis pathogenesis

A
  • Unknown
  • believed to be variation of one of the other non-LCH disorders
  • association with haematologic malignancies - mast cell leukaemias, AML and low grade B cell lymphoma
27
Q

Indeterminate cell histiocytosis clinical

A
  • Commonly involves the trunk and extremities, but can occur elsewhere
  • Forms:
      1. Generalized - firm, red-brown papules, <1 cm
      1. Solitary - single, soft erythematous lesion
  • Can ulcerate
  • As progress, become brown-yellow
  • Waxes and wanes
  • Extra-cutaneous:
    • corneal and conjunctival
    • visceral involvement has been reported so need close monitoring
28
Q

Indeterminate cell histiocytosis histopath

A
  • Monomorphous infiltrate of histiocytes
  • Histiocytes have oncocytic appearance
  • Epidermotropism less common
  • Touton giant cells
  • Immunophenotype:
    • Positive for S100,m CD1a, CD68, CD163, HAM56, lysozyme, alpha-1 antitrypsin, HLA-DR, CD11c, CD4b and factor 13a
    • Negative for CD207 - Langerin
29
Q

ICH ddx

A
  • Generalised eruptive histiocytoma, JXG, congenital self-healing reticulohistocytosis
  • Benign cephalic histiocytosis
  • Eruptive syringomas, UP, lymphomatoid papulosis
30
Q

ICH treatment

A
  • self-limited or non-progressive
  • really bad –> chemotherapy
  • reports of thalidomide, isotretinoin, MTX, NBUVB, PUVA, TSEB
  • Given can get visceral - requires long term follow up
31
Q

Benign cephalic histiocytosis epi

A
  • ~ 60 cases reported worldwide

- occurs by age 1, always within first 3 years of life

32
Q

Benign cephalic histiocytosis pathogenesis

A
  • Unknown
  • similar immunohistochemical profile to JXG
  • maybe just park of a spectrum with JXR and eruptive histiocytoma
33
Q

Benign cephalic histiocytosis clinical

A
  • 2-5 mm, pink-red and red-brown macules nad papules initially on the face, and then appear on the ears and neck, very occasionally spreads elsewhere
  • eventually flatten, leaving a residual hyperpigmentation
  • one report of diabetes insipidus, otherwise really healthy
34
Q

Benign cephalic histiocytosis histo

A
  • Three patterns:
    • Dermal papillary
    • Diffuse
    • Lichenoid
  • Histiocytes - can be pleomorphic, round, regular
  • can have Touton giant cells
  • Markers: CD11b, CD11c, CD14b, CD68, HAM56, factor 13a –> usually only stain for CD68 and CD163 though
35
Q

Benign cephalic histiocytosis ddx

A
  • UP
  • LCH
  • JXG
  • Eruptive histiocytoma
  • Indeterminate cell histiocytosis
36
Q

Benign cephalic histiocytosis treatment

A
  • generally a self limiting disorder

- regular examination

37
Q

Generalized Eruptive Histiocytoma epi, path, clinical

A

Epidemiology
- Very rare
- 3rd-6th decade of life, kids <4 years
Pathogenesis
- not known
- may be on same spectrum as benign cephalic or an eraly, indeterminate stage of non-LCH
Clinical
- Recurrent crops of red to brown papules –> hundreds of papules less than 1 cm in diameter, on trunk, proximal extremities and occasionally on the face
- Usually symmetric, and mucosal surfaces occasionally involvemed
- Resolution within months - PIH or small scars
- In kids may be more xanthomatous

38
Q

Generalized eruptive histiocytoma histo, ddx, rx

A

Histo
- Sup-mid dermis - nearly uniform infiltrate of histiocytes with a few lymphocytes, rarely lichenoid
- Xanthomatous cells are rare, but can see spindled
- Stains: lysozyme, alpha-1 antitrypsin, CD11b, CD14b, CD68 and Factor 13a
Ddx
- LCH
- UP
- Eruptive syringomas
- Papular GA
- Non-LCH disorders
Rx
- None rewuired
- Occasionally roaccutane, cryotherapy, PUVA
- Rarely leukaemia

39
Q

Reticulohistiocytosis epi

A
  • predominantly Caucasian adults
  • multicentric: super uncommon, occurring in women in their 40s
  • Giant cell: young adults
40
Q

Reticulohistiocytosis pathogenesis

A
  • unknown
  • suggested TB
  • ?after trauma
41
Q

Giant Cell Reticulohistiocytosis clinical

A
  • single, asymptomatic yellow-red nodule
  • patients are otherwise healthy
  • spontaneously resolves
42
Q

Multicentric Reticulohistiocytosis clinical - cutaneous

A
  • Cutaneous and mucous membrane
  • Pink, red-brown to yellow papules
  • Acral, head, hands, fingers, ears, articular regions
  • Papules and nodules: oral, pharyngeal, nasal mucosae
  • Rare: leonine facies, photodistribution, nail changes
43
Q

Multicentric Reticulohistiocytosis clinical - extracutaneous

A
  • Arthropathy
    • 6-8 year course of symmetric, erosive arthritis –> 45% develop arthritis mutilans
  • Other:
    • Hyperlipidaemia, positive TB, vasculitis, autoimmune
    • 25-30% associated malignancy
    • Rarely, monoclonal gammopathies, cryoglobulinaemia
    • Heart, eye, lungs, thyroid, liver, kidney, bone marrow, etc
  • Spontaneously remits within 5-10 years
44
Q

Reticulohistiocytosis Histology

A
  • Circumscribed, non-encapsulated dermal and synovial infiltrate of multinucleate histiocytes
  • Histiocytes have eosinophilic ground glass, they are more angulated in appearance
  • Can have plasma and eosinophils
  • For solitary, have more neutrophils, spindle cells and greater frequency of xanthomatous changes
  • Stain: CD68, CD11b, CD45, HAM56, negative for S100 and Mac387
45
Q

Reticulohistiocytosis Ddx

A
  • Solitary nodule –> super broad ddx, adult xanthogranuloma
  • Multicentric:
    • rheumatoid arthritis
    • dermatomyositis
    • other histiocytoses: generalized eruptive histiocytosis, Rosai-Dorfman
46
Q

Reticulohistiocytosis Rx

A
  • Surgical excision

- Systemic: NSAIDs, steroids, MTX, cyclophosphamide, TNF alpha blockers

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