Diagnosis reserved

Case 1890  25.8.17 (R. Carr)  M 45 nodule on shin 

Collision of pathologies.  Lymphoid follicle pattern.  Poorly circumscribed dermal tumour with dark cells, hyalinized cells and foci of calcification. Some islands of dark cells show palisading. Eosinophils in the infiltrate.  Reported as low-grade follicular neoplasm (probably benign) with ALHE-like stromal reaction. 

Case 1893  30.8.17 (R. Carr)  F 60 fixed rash outer thighs “Fibromyalgia” 

Pseudo lymphomatous/reactive plasmacytosis . 

Several biopsies over the years.  Red cell extravasation; plasma cells; RDD-like histiocytes.  All serology tests -ve 

DD suggested: Rosai-Dorfman disease; Lyme disease; IgG4 diseases; Castleman disease 

Ref: Cutaneous pseudolymphoma.  Mitteldorf C, Kempf W. J Cutan Pathol 2020; 47(1): 76-97 

Case 1919  6.10.17  (A. Bakshi)  F 45 ante-cubital fossa 

Either fibroma of tendon sheath (doesn’t seem likely at this site) or desmoplastic fibroblastoma.  Doesn’t fit either very neatly. 

Case 1961 5.12.17  (U. Sundram)  M 67 penile lesion 

Gross compact hyperkeratosis resembling acral skin.  No dysplasia.  Too gross for pseudoepitheliomatous keratotic and micaceous balanitis (PKMB).  Best fit would be epidermal naevus, but doesn’t fit with history. 

Case 2001  6.2.18  (IH Chaudhry)  M 75 neck lesion 

Small basophilic papule with invaginated surface.  Cells look a bit like poroma but not quite right.  BerEP4 +ve in part.  Opinion very varied – signed out as “adnexal tunour – favouring sebaceous carcinoma (in situ). 

Case 2012 21.2.18 (IH Chaudhry)  F 85 arm H/O poor prognosis thyroid ca 

Signed out as PRP but not at all typical histologically.  Clinical photgraphs are barn-door psoriasis not PRP. 

Case 2071  15.5.18  (U. Sundram)  M 77 recent onset pigmented papule shoulder 

Favoured regressing naevus> regressing melanoma because cells are small and not particularly atypical 

DD:  PEM/animal-type melanoma – these tend to have larger, more epithelioid cells. 

Case 2078  24.5.18 (IH Chaudhry)  - no clin details 

Superficial and deep periv and periadn infiltrate.  Favoured Jessner’s but I think there is some epidermal involvmenet putting it more into tumid LE for me. 

Case 2812  16.4.21 (R.Carr)  M 75 nasal cavity mass.  H/O ocular melanoma 

S100, Sox10, HMB45 all neg.  MelanA equivocal.  Awaiting diagnosis by ENT. 

Case 2827  7.5.21  (R. Carr)  F 75 4 month history of red/purple discolouration hip and down leg.  PMR on steroids 

RC suggested Sweetoid intravascular histiocytosis as a manifestation of PMR.  Resolved on increasing steroids. 

Case 2916 9.9.21 (S. Taibjee)  M 46 polymorphic rash elbows, back and legs 

dense perivascular and interstitial infiltrate comprising lymphocytes, histiocytes, neutrophils and numerous eosinophils with flame figures.  Some intra-epidermal and subepidermal clefting.  Working diagnosis allergic granulomatosis with polyangiitis (formerly Churg-Strauss), but awaiting further clinical correlation. 

Case 2937  8.10.21 (R. Carr)  M 34 thigh.  Enlarging pink macule, partially pigmented. 

Superficial atypical melanocytic proliferation of uncertain significance (SAMPUS).  Negligible metatstatic potential.  Reserves MELTUMP for thicker lesions with vertical growth and higher potential for metastasis. 

Case 2977  3.12.21 (R. Carr) F 80 8y history of scaly lesion on leg 

I favoured annular lichen planus with central atrophy.  Signed out as atrophic seborrhoeic keratosis.  P16 mosaic, p53 and Ki67 show peripheral graded pattern typical of benign or reactive hyperplasia. 

Case 2989 21.12.21 (U. Sundram)  F 84 inguinal lesion 

Pattern of cutaneous metastasis.  Patient had a locally aggressive SCC and previous history of Merkel cell carcinoma. CK7+ve/CK20 -ve.  Signed out as poorly differentiated carcinoma. 

Case 4108 19.10.22 (H. Diwan) M 51 groin 

This was posted as porokeratosis ptychotropica.  However, the diagnostic histological features of porokeratosis were absent, and the lesion was in the groin, not the buttocks which is the usual site for this rare form of porokeratosis.  I thought this was a viral wart.  Others had reservations about the proffered diagnosis, too. 

Case 4027  28.6.22 (U. Sundram) F 65 rash, face 

Dense dermal infiltrate with granulomatous pattern and suggestion of numerous inclusions.  All work-up for infectious aetiology negative.  Called “granulomatous rosacea”, but this is debateable.