Mycosis fungoides (MF) is a primary cutaneous T-cell lymphoma that may, although rarely, present as asymptomatic hypopigmented lesions. On the other hand, vitiligo is an autoimmune disorder characterized by asymptomatic depigmented patches. Few reports have documented both conditions occurring in a single patient, making this an intriguing diagnostic and management dilemma.

This is a case of a 26-year old female with a 10-year history of persistent hypopigmented, depigmented and erythematous patches and thin plaques [Figures 1a and 2a]. Histopathology showed epidermotropism of mononuclear cells on H&E stain [Figure 3] and a positive CD-3 stain for T cells, confirming mycosis fungoides [Figure 4b]. No evidence of lymphadenopathy and visceral involvement was found on both the chest and abdominal CT scans. The depigmented patches were likewise biopsied showing lack of Melan-A staining and absence of epidermal melanocytes, consistent with vitiligo [Figure 4a]. Final diagnoses were both mycosis fungoides, stage IB and vitiligo. The patient underwent narrowband UVB phototherapy and was started on topical corticosteroids [Figures 1b and 2b]. Improvement was evident over a three-month period, with body surface area decreasing from 77% to 46%. As the patient is young, has normal LDH levels, and shows no signs of extracutaneous disease, prognosis is promising.

This rare case of mycosis fungoides and vitiligo occurring together presents notable diagnostic and management challenges. Some studies hypothesize that the aberrant T cells involved in MF might contribute to the T cell-mediated destruction of melanocytes, similar to the mechanisms seen in vitiligo.