sQuiz your knowledge! When plaques turn into tumours

A 37-year-old woman presented with a history of chronic erythematous plaques on the trunk, initially managed with UV-B phototherapy. After several months of irregular follow-up, she was re-admitted with multiple ulcerated nodules on the face and upper back, associated with malaise and lymphadenopathy (figure 1A-D). PET-CT revealed metabolically active lymph nodes and visceral involvement. Histopathology showed dermal infiltration by atypical lymphocytes expressing CD3 and CD4 (figure 1E-H), with loss of CD7 and CD26.What is your diagnosis?Answer: Advanced-stage mycosis fungoides (stage IV)
This case illustrates the aggressive transformation of a cutaneous T-cell lymphoma, evolving from patch-plaque lesions to the tumoural stage with extracutaneous spread. The patient initially responded to UV-B phototherapy but later developed rapidly progressive ulcerated nodules and lymphadenopathy. PET-CT confirmed nodal and visceral involvement, consistent with advanced-stage disease.
Histopathology and immunophenotyping revealed CD3⁺, CD4⁺ T-cells with loss of CD7 and CD26, confirming the clonal proliferation characteristic of advanced mycosis fungoides. Tumoral transformation occurs in approximately 10-20% of patients and is associated with extensive lesions, delayed diagnosis, and adverse ­immunophenotypic features [1].
Treatment follows a stepwise approach: topical and phototherapy regimens for early stages, and systemic therapies, such as bexarotene, interferon-α, or chemotherapy, for advanced disease [2, 3]…