Horng-Shin Lin’s research while affiliated with Chung Shan Medical University and other places

Erythema induratum (EI) is clinically characterized by recurrent crops of tender nodules on the lower legs and lobular panniculitis with granulomatous inflammation and pathologically characterized by vasculitis and focal fat necrosis. Currently, many authors consider EI to be a multifactorial disorder with diverse causes, including Mycobacterium tuberculosis and hepatitis C infection. Here, we report a case of a 65-year-old female with a 1-year history of recurrent crops of tender nodules and plaques on her bilateral lower legs. In addition, she had suffered from a chronic cough with sputum for 1 year and had contact history with pulmonary nontuberculous mycobacterial infection from her husband. The histopathological findings of the skin biopsies were consistent with the diagnosis of EI. Chest computed tomography revealed multiple lymphadenopathy and two sets of sputum cultures showed M. abscessus. After 2 months of anti-nontuberculous mycobacterial therapy with ciprofloxacin, the skin lesions resolved completely and there was no recurrence within the following year.

CASE REPORT A 48-year-old man presented with a reddish skin tumor over face for three months. He denied any systemic disease and history of insect bite. The skin examination revealed a reddish dome-shaped elastic fi rm nodule, 1.2 cm in diameter, over left zygomatic area (Fig. 1). Other physical exam did not show any abnormal findings such as lymphadenopathy or hepatosple-nomegaly. The nodule was partially excised for pathological examination. The histopathology revealed superficial and deep patches of atypical lymphoid cell infiltrates around the append-ages with a characteristic lymphoepithelial pattern and Grenz zone. The infi ltrate is composed of small lymphocytes, centrocyte-like cells, and plasma cells admixed with a small proportion of large blastoid cells (Fig. 2). Immunohistochemical stains showed that the infi ltrate was strongly positive for CD20 and Bcl-2 (Fig. 3). A complete blood count, liver and renal function, lactate dehydrogenase, and serum immunoglobulin analysis were normal, and hepatitis B/C serology and HIV tests were negative. A positron emission tomography (PET) scan did not show any evi-dence of systemic involvement. After total excision of the lesion, he was regularly followed up without local recurrence at our clinic for more than half a year.