PMC10439773_01
Granulomatous mycosis fungoides. (A) Clinical features demonstrate multiple ill-defined erythematous indurated plaques on both legs, the lesion on the right leg showed large overlying ulceration. (B) Atypical lymphoid cell infiltrate with granulomatous reaction on histology (H&E x40) (inset, x400).
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A 72-year-old female with type II diabetes and hypertension first presented in January 2020 with a 1-year duration of chronic progressive indurated erythematous plaques on both legs, with ulceration on the right leg (Figure 1A). Skin biopsy showed dermal atypical lymphoid infiltrate with granulomatous reaction (Figure 1B), positive on immunohistochemistry for CD2, CD3, CD4, CD5, and CD7 and negative for CD8, CD20, CD30, CD34, and CD56.
New round erythematous plaque on her right leg (A) and nodule on the left leg (B), measuring 2-3 cm in diameter with ulceration and central necrotic crust. The preexisting granulomatous mycosis fungoides shows large ulcerative brownish plaque on the distal leg (B).
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Twenty-seven months following MTX initiation, at a dosage of 15 mg/week, the patient reported an eruption of a round erythematous plaque on her right leg and a nodule on the left leg, measuring 2-3 cm in diameter with ulceration and central necrotic crust (Figure 2A and B). This was in addition to preexisting large brownish ulcerative plaques on her lower legs (Figure 2B).
Histopathology from the new lesion on the left leg shows dense, diffuse atypical large mononuclear cell infiltration in the entire dermis (H&E x40); monomorphous atypical large lymphocytes of centroblastic morphology with frequent mitotic figures (inset, x400).
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Biopsy from the new nodule on her left lower leg showed dense, diffuse atypical monomorphous large lymphoid infiltrate involving the entire dermis (Figure 3).
Immunohistochemistry of cutaneous methotrexate-related Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma shows positive (A) CD20, (B) CD30, (C) Ki-67 (>90%), and (D) EBV encoded RNA by in situ hybridization (EBER-ISH) but negative (E) CD3 and (F) CD 56 staining of atypical lymphoid cells (H&E x400).
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CD30, MUM1, and Ki-67 (>90%), but not CD2, CD3, CD4, CD5, CD7, CD8, CD10, CD56, LANA1, and BCL6 stains (Figure 4). Computed tomography imaging of the chest and abdomen revealed no evidence of systemic involvement.