Mycosis fungoïde with CD30 large cell transformation accompanied by hidden adenocarcinoma of the colon: a case report

Mycosis fungoides is the most common subtype of primary cutaneous T-cell lymphoma, its evolution is indolent, except in the case of transformation into large T-cell lymphoma. A 63-year-old patient, he has a stage IB mycosis fungoid for 4 years treated by topical corticosteroids associated with methotrexate. Then he had progressed to stage IIb, treated by PUVA (photochemotherapy) and acitretin with complete remission and then relapsed, with the appearance of tumors, and adenopathy, the extension assessment had objectified a transformed CD30 mycosis fungoid, with a lymph node localization of T lymphoma, the patient is classified as stage IIIB. Thoracic-abdomino-pelvic CT had shown a thickening of the sigmoid colon wall, completed by colonoscopy, whose colon biopsy had objectified a colonic adenocarcinoma. The association of colonic adenocarcinoma and a mycosis fongoide is rare, a pathophysiology is poorly understood, suggests a probably genetic predisposition.