Contributed by Amer Heider, MD and Jonhan Ho, MD
The patient is a 39-year-old white female presented with a 5 x 5 mm erythematous isolated papule on right forearm.
The specimen was received in 10% buffered formalin labeled as right forearm lesion. It consisted of a portion of skin with underlying soft tissue, measuring 1.2 x 1.0 x 0.2 cm. The tissue is tan rubbery, partially lobulated and the cut surface shows myxoid areas. The specimen was inked, serially sectioned and totally submitted for histological evaluation.
Evaluation of the histologic sections demonstrated a shave biopsy of skin and subcutaneous tissue that showed an unencapsulated lesion located in the dermis with focal extension to subcutaneous fat lobules (Figs 1, 2 and 3). The mass is lobulated with fibrovascular septae between the variable size lobules. It appears to spare the papillary dermis (Fig. 4). The tumor is composed of spindle and stellate cells with a pale cytoplasm in a myxoid stroma (Figs. 5 and 6). Some lobules show round epithelioid cells with abundant eosinophilic cytoplasm and conspicuous vesicular nuclei (Figs. 7 and 8). Occasional hyperchromatic nuclei, very rare mitotic figures and multinucleated giant cells are seen (Figs. 9 and 10).