Case report
A 50-year-old man visited the outpatient dermatology clinic of Faghihi Hospital (Shiraz, Iran) in December 2021 with the chief complaint of a rapidly growing lesion on his temple area. The patient had noticed a small round lesion that appeared abruptly, with rapid growth during the last two months. There was no sign or symptom of pain, tenderness, pruritis, bleeding, discharge, or hypoesthesia. Skin examination revealed a solitary, round, firm, 1×1.2 cm erythematous nodule with a sharp, well-defined border on the patient’s temporal area (Fig. 1). Neither lymphadenopathy nor any other systemic symptoms were found in the general examination. The patient had no specific history of surgery, rheumatoid arthritis, malignancy, or any other disease or medication usage. There was also no family history of similar cutaneous lesions or other diseases.
An excisional biopsy with a safety margin of 0.5 mm was taken under local anesthesia. The specimen was fixed in formalin and studied by an expert dermatopathologist. The histopathologic study revealed thinning of the epidermis with a dense partly diffuse partly nodular infiltration of small to medium-sized atypical lymphocytes and a few large atypical lymphocytes, plasma cells, and histiocytes scattered in the entire dermis, extending to the subcutaneous fat. The infiltrate was separated from the dermis by the grenz zone (Fig. 2).
Immunohistochemical studies revealed that 90% of the lymphoid cells were CD4+, a few CD8+, and the majority of those cells were positive for CD3, CD5, and CD7, but negative for CD30, CD20, BCL6, CD10, PAX 5, and MUM1. Ki67 was 10% (Table 1) (Fig. 3). The final diagnosis was primary cutaneous CD4+ small to medium T- cell lymphoproliferative disorder. Further laboratory tests were normal, including a complete blood count and lactate dehydrogenase assay. The biopsy specimens were reviewed by a dermatopathologist, who confirmed the mentioned findings. No significant signs of recurrence were observed over two months of follow-up.