Tumorous formation of the forehead.

T‑cell non-Hodgkin's lymphoma (NHL) represents approximately 10% to 15% of all lymphomas in Western countries. We present the case of a 16-year-old girl with nodular erosive tumor formation on the forehead within the previous 3-4 months and clinical evidence of cervical and submandibular lymphadenopathy in parallel. Tuberculosis verrucosa cutis, lupus vulgaris, cutaneous leishmaniasis, pyoderma faciale, sporotrichosis, infected insect bite, B‑cell lymphoma, and atypical acneiform eruption were considered in the differential diagnosis. The patient has undergone therapy with oral ciprofloxacin (2 × 250 mg/d) for 10 days and oral amoxicillin/clavulanic acid (2 × 1 g/d) for 7-8 days, followed by oral clindamycin (2 × 300 mg/d) and oral rifampicin (2 × 300mg/d) for 4 weeks-all without any improvement. Unfortunately, disease progression was observed. Histologic examination revealed evidence of peripheral T‑cell non-Hodgkin's lymphoma, and the subsequent immunohistochemical study confirmed the diagnosis, showing positive CD3 and CD4 expression and negative CD8, CD20, CD30, CD43, and ALK1 expression. Based on CT, lymph node involvement was found above and below the diaphragm, such that T‑cell lymphoma stage 4E was concluded. CHOEP chemotherapy treatment was initiated, with a favorable clinical outcome after the first cycle.