Lesions Flashcards
(40 cards)
Which lesions may show peripheral pallisading?
BCC
Trichoepithelioma, Trichoblastoma
Trichofolliculoma
Trichilemomma
In what lesions can you see Pagetoid spread?
Paget's disease Melanoma Special site naevi Pigmented spindle cell naevus of Reed Pagetoid Bowens disease Sebaceous carcinoma Apocrine carcinoma Merkel cell carcinoma - rarely NB atypical lymphocytes in epi in MF can resemble Pagets but usually referred to as epidermotropism and not pagetoid
What is DD of malignant spindle cell tumours of the dermis?
How do you distinguish?
SLAM DUNK
Spindle cell SCC - CK5/6
Leiomyosarcoma - desmin, smooth muscle actin (SMA)
Angiosarcoma - CD31 + 34
Melanoma (spindle/desmoplastic) - S100 + MelanA
DFSP - CD34 (factor 13a neg)
Undifferentiated pleomorphic sarcoma (AFX)-CD10, CD99
Nodular fasciitis - HSP47, actin
Kaposi’s sarcoma - HHV8 (also CD31 + 34)
Causes of Big blue balls in the dermis?
Cylindroma Spiradenoma Hidradenoma Sebaceous tumours BCC Trichilemomma Glomus tumour
What is the differential for a blue cell tumour in the dermis?
Merkel cell carcinoma CK20 or CAM 5.2 paranuclear dot positivity
Lymphoma LCA
Pseudolymphoma
Metastatic small cell carcinoma of the lung TTF1
BCC
Melanoma S100, HMB45
SCC - if areas of squamous differentiation CK5/6
Which tumours show stroma-stroma clefting
Classicially;
Trichoepithelioma
Trichoblastoma
Occassioanllly seen in other lesions
What is DD for dirty socks appearance of epi?
Solar lentigo PUVA lentigo Seb keratosis Large cell acanthoma Dermatofibroma Lentigo maligna Dowling Degos disease or Galli-Galli disease
Extramammary Paget’s disease IHC
CD23 +ve in mammary and extramammary Paget’s
EMPD is positive for pankeratin markers AE1/3, EMA, CEA, CK7
Do melanoma stains to exclude melanoma
Negative for S100, other MM markers and CD44
Pos GCDFP-15 and neg CK20 favours primary EMPD or cutaneous tumour
Pos CK20 and neg GCDFP-15 favours secondary disease of endodermal origin (internal malignancy)
Main DDs are MM and IEC
What are the poor prognostic histo features for Merkel cell carcinoma ?
5DDD tumour 5mm or larger Dense mononuclear inflammatory cell infiltrate Deep extension into subcutis Diffuse growth pattern
IHC for mammary Paget’s disease
positive for CEA, EMA, CAM 5.2 and usually positive for S100 (nb EMPD is S100 -ve)
PAS +ve and diastase resistant
CD23 +ve in mammary and extramammary Paget’s
What are important points in leiomyosarcoma?
Painful
Any mitoses at all in a dermal smooth muscle tumour is enough to call it leiomyosarcoma
If confined to dermis - no metastatic potential
If extends into fat - risk of mets
stain w/ desmin or smooth muscle actin
How do you distinguish Glomus tumour and Glomulovenous malformation?
If mainly solid tumour with a few vascular channels its a glomus tumour
If mainly vascular spaces and little solid tumour its a glomulovenous malformation (glomangioma is old name)
What are the DDs for a dilated pore of Winer?
Pilar sheath acanthoma - shallow
Trichofolliculoma - large and branching
What are the features of Langerhans cell histiocytosis?
what are the special stains?
What special test can be done and what is the finding?
Papillary dermal infiltrate of blue cells
cells have reniform, coffee bean nuclei
can be Langerhans cell epidermotropism
May have pseudo-pautrier (Langerhans cell) microabscesses
Overlying epi may be eroded
stains +ve for S100, CD1a, Langerin (CD207)
NB EM shows cytoplasmic Birbeck ganules expressing CD207 (tennis racket shaped inclusions)
How do you distinguish sebaceous adenoma and sebaceoma?
Sebaceos adenoma has mainly clear sebaceous cells (adenoid means glandular)
sebaceoma hs mainly dark blue cells and only scattered clear cells
Acantholytic dyskeratosis – DDs
Grovers - only one thats significantly spongiotic; varying degree of FOCAL Acanth & Dysk
Dariers – some acantholysis, lots of dyskeratosis, can be benign AK-like change in adjacent epi
Hailey-Hailey – lots of acantholysis, little dyskeratosis (dilapidated brick wall)
Epidermal naevus
Warty dyskeratoma
Acantholytic dyskeratoma
NB pemphigus vulgaris has acantholysis w/out dyskeratosis (tombstoning)
Which tumours arise from an organoid naevus?
SCAP trichoblastoma BCC SCC KA
What are the features of a neurofibroma?
bland wavy neural spindle cell dermal tumour fibrillar stroma - 'shredded carrot' Mast cells Grenz zone S100 +ve
Which lesions can appear to be attached to the epidermis by struts
T-FIRE
Tumour of the follicular infindibulum - most typical
Fobroepithelioma of pinkus (pink between struts-pinkas)
Inverted follicular keratosis
Reticulated seborrhoeic keratosis
Eccrine poroma
What are the features of an inverted follicular keratosis?
well circumscibed dermal tumour (benign architecture)
kertin cysts
squamous eddies - characteristic
may be follicular structures
Some mitoses and atypia but not malignant
Basically an endophytic irritated seb K
What are the features of a Spitz naevus?
Nests of cells in epi but no pagetoid spread
Composed usually of spindle shaped melanocytes but can be epithelioid cells or mixed
Clefting around nests
shoals of fish or ‘raining down’ growth pattern
kamino bodies in epi
few mitoses, little pleomorphism
P16 +ve (like benign naevi)
HMB45 +ve in junctional but not deeper part (like benign naevi)
Which stains are positive in BCC?
histo viva 2014
BerEp4 most specific (but alos posiitve in trichoepithelioma or DTE
Bcl2 also positive
Many plasma cells lesion differential?
SCAP
Kaposis sarcoma
cutaneous plasmacytoma
Grenz zone DDs
Granuloma faciale AFX Neurofibroma Dermatofibroma Colloid milium Acrodermatitis chronica atrophicans Lepromatous leprosy Pseudolymphoma Borrelial lymphocytoma Lymphoma - types; - CD30+ cALCL - MF (rarely) - Marginal zone B cell lymphoma - Follicle centre B cell lymphoma - Diffuse large B cell lymphoma, leg type
