A Challenging Case of Granulomatous Mycosis Fungoides Mimicking Cutaneous Sarcoidosis

Abstract

Granulomatous mycosis fungoides was first described by Ackerman and Flaxman in 1970 and is characterized histologically by diffuse invasion of dermis by giant cell lymphocytes. Granulomatous mycosis fungoides is a subtype of cutaneous T-cell lymphoma which is a variant of non-Hodgkins lymphoma. It usually affects middle-aged adults, presenting as progressive skin lesions. Initial diagnosis can be extremely challenging as it mimics various dermatopathies both clinically and histologically. Despite advances in diagnostic techniques, diagnosis is often delayed, as granulomatous mycosis fungoides is a great imitator. We describe a unique case of a 51-year-old female presenting with cutaneous granulomatous infiltration, which was initially diagnosed as sarcoid granulomatous dermatitis; and after 6 years of evolution, was eventually determined to be granulomatous mycosis fungoides. We discuss the rare presentation of granulomatous mycosis fungoides misdiagnosed as sarcoid granulomatous dermatitis and the challenges encountered in confirming the lymphoma diagnosis. Clinicians and pathologists should consider this entity in differential diagnosis, when encountered with persistent granulomatous skin lesions, as extensive granulomatous lesions tend to obscure the underlying lymphoma. Immunophenotyping and molecular gene rearrangement studies can improve diagnostic accuracy.




J Med Cases. 2019;10(4):106-109
doi: https://doi.org/10.14740/jmc3276