Anaplastic lymphoma kinase negative sarcomatoid variant of anaplastic large-cell lymphoma presenting as a malignant fibrous histiocytoma.

It has been reported that 25–60% of anaplastic large cell lymphomas (ALCL) carry the t(2;5)(p23;q35) translocation that results in the production of a novel chimeric protein anaplastic lymphoma kinase (ALK). Because ALK-positive ALCL has a more favorable prognosis than ALK-negative ALCL, recent investigations have suggested subclassification of ALCL according to ALK expression [1]. The sarcomatoid variant of ALCL is an extremely rare condition, which is easily misdiagnosed as high-grade sarcoma [2]. The ALK expression of sarcomatoid lymphoma has seldom been assessed. We report a case of sarcomatoid ALCL presented as malignant fibrous histiocytoma with evaluation of ALK expression. A 51-year-old man presented at another hospital with a 2-month history of an enlarging superficial mass in his left groin. The diagnosis based on biopsy results was high-grade sarcoma, probably a myxoid malignant fibrous histiocytoma. The patient was referred to our hospital. Physical examination revealed a soft, ulcerated, infected, immobile tumor which bled easily measuring 23 23 cm in the left groin (Fig. 1). Bacterial cultures of the tumor demonstrated more than ten types of Gram-positive and Gram-negative bacteria. Magnetic resonance imaging