Mycosis fungoides and CD30+ cutaneous T-cell lymphoma simulating pyoderma gangrenosum in a patient with ulcerative colitis

Abstract

Background: Pyoderma gangrenosum is estimated to occur in 5% to 12% of ulcerative colitis patients. Primary CD30+ cutaneous large cell lymphoma is the second most common cutaneous lymphoma. It may coexists with mycosis fungoides.

Main observations: We report a 38-years-old female patient with 12 year history of ulcerative colitis, treated previously with 5-aminosalicylic acid and systemic corticosteroids. The disease has been in remission for the past 1.5 years, with no maintenance treatment. The patient then developed a rapidly progressing ulcerated lesion clinically simulating pyoderma gangrenosum. Physical examination revealed also a small number of hairless hypopigmented patches on the upper and lower limbs which she claimed to have appeared 4 years ago. Surprisingly a histological evaluation of the ulcer revealed a CD30+ primary cutaneous large cell lymphoma, while histology of hypopigmented lesions revealed mycosis fungoides, patch stage. T-cell receptor gene rearrangement from the two lesions didn't reveal the same T Cell clonalitiy and the patients lymphoma was stable.

Conclusion: Our case presents the rare coexistence of primary mycosis fungoides and primary CD30+ cutaneous large cell lymphoma, rather than the CD30+ cutaneous large cell lymphoma developing from mycosis fungoides. This case also presents the development of a pyoderma gangrenosum-like lesion of CD30+ cutaneous large cell lymphoma in a patient with ulcerative colitis. An observation that emphasizes the need for a high index of suspicion in cases diagnosed as pyoderma gangrenosum based solely on clinical appearance.

Keywords: cutaneous T-cell lymphoma; inflammatory bowel disease; mycosis fungoides; pyoderma gangrenosum; ulcer; ulcerative colitis.

Figure 1

Histology from the border of the PG like lesion on the right thigh, revealing lymphoid aggregates composed of large atypical cells throughout the whole dermis with epidermotropism (A,B). Immunohistochemically the lymphoid cells were positive for CD30 stain (C,D).