Cutaneous T cell lymphoma mimicking cutaneous histiocytosis: differentiation by flow cytometry

A two-year-old, neutered female cross-bred labrador had multiple cutaneous nodules, biopsies of which revealed pathological changes consistent with cu taneous histiocytosis. During a period of one month the dog developed multi centric lymphadenopathy, a retrobulbar mass and masses within the quadricep s and cervical muscles. Fine needle aspiration cytology of the cutaneous no dules and lymph nodes and histological examination of the cutaneous nodules and muscle masses suggested the presence of lymphoblastic lymphoma. A defi nitive diagnosis of CD8+ T cell lymphoma was achieved by immunophenotyping the tumour cells by flow cytometry.