DP11 Dermal plexiform spindle cell lipoma: a perplexing entity

Abstract We present a 66-year-old man who presented to dermatology with an unusual lesion. An outdoor worker prior history of melanoma, the patient was referred new pigmented lesion adjacent his melanoma scar. This identified as seborrhoeic keratosis and reassured. Following full body examination, incidental on left anterior shoulder. The measured 9 × 7 mm, dermal-based, dome-shaped, soft palpation skin coloured light peripheral pigmentation. featureless upon dermoscopic examination. clinical differential diagnosis included neurofibroma intradermal naevus. narrowly excised. Histological examination revealed ill-defined, wedge-shaped dermal tumour fascicles vaguely plexiform arrangement. widely separated comprised loosely arranged spindle cells, mature adipocytes scant collagen fibres myxoid stroma. cells were stained diffusely CD34 immunohistochemistry. proportion (around 20–30%) S100. features in keeping cell lipoma. Spindle lipoma is uncommon benign, histologically distinct tumour, accounting for 1.5% all adipocytic neoplasms. More common within subcutis, it rare these lesions purely location. Dermal lipomas tend be less cellular than their subcutaneous counterpart. coupled variable representation three constituent components (spindle fibromucinous stroma) results wide range possible diagnoses. variant (PSCL) poorly recognized form even greater potential misdiagnosis, particularly neurofibroma—­leading erroneous neurofibromatosis. PSCL exceptionally only eight cases reported literature thus far. Here, we report further case lipoma, with, first-time, corresponding images. In our summary, discuss detail diagnostic pitfalls this how best employ immunohistochemical staining avoid them.