BAPOMA (Wiesner naevus -2011)

Case 1100  10.9.14  (H. Diwan)  F 44 arm ?BCC 

Vaguely naevoid architecture but confluent pattern.  Cell types vary from small hyperchromatic naevus-type cells to larger atypical epithelioid cells.  BAP-1 –ve; VE +ve. 

Case 1151  20.11.14 (H. Diwan)  F 24 chest lesion 

Superficial naevoid clusters.  Looser deeper collection with more cellular pleomorphism and epithelioid pattern and some giant cells.    BAP1 –ve. 

Case 2406  19.9.19   (IH Chaudhry) F 18 pigmented lesion on arm 

Well demarcated, pushing melanocytic lesion. 

Mixed population of normal small banal naevus cells, and larger cells with pink cytoplasm looking histiocytoid/Spitz – like BAP-1 –ve, also some lymphocytic infiltration. 

These BAP-1 inactivated melanocytic tumours can be familial, multiple and assoc. with uveal carcinoma and mesothelioma 

Ref: Garfield EM.  JAAD 2018: 79(3) 525-34 

Case 2901  19.8.21 (R. Carr)  F 18 cheek ? intra-dermal naevus 

Intradermal naevus with loss of nuclear BAP1 staining (although cytoplasm +ve).  Also called MBAIT - melanocytic BAP1-mutated atypical intradermal tumour. 

Case 4484 28.3.24 (Prof. B. Vergier) F 35 changing lesion thigh 

BAP1 epithelioid melanocytic tumour 

DD: Spitz; SSM; atypical Spitz; Spitzoid melanoma