Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
Department of Dermatology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
Int J Infect Dis. 2023 Sep;134:88-90. doi: 10.1016/j.ijid.2023.05.004. Epub 2023 May 16.
Mycobacterium genavense is a rare type of nontuberculous Mycobacterium that has been reported to cause disseminated infections in patients who are immunocompromised. Because M. genavense is slow-growing and poorly able to form colonies on Ogawa medium, genetic and molecular analyses are necessary to identify this pathogen. Nontuberculous Mycobacterium infections present with various cutaneous manifestations. Of these, rare cases have been reported to present with mycobacterial pseudotumors. However, there are no reports of M. genavense with cutaneous pseudotumors. In this paper, we report a case of a pseudotumor due to M. genavense infection that was observed only in a cutaneous lesion. The patient was taking 5 mg of prednisolone and was aware of a tumor on the right lower leg. Biopsy samples showed diffuse spindle-shaped histiocytes and various other inflammatory cell infiltrates, and Ziehl-Neelsen staining detected Mycobacterium. Because no colonies formed on the Ogawa medium, genetic testing was performed, and M. genavense was identified by DNA sequence analysis. There were no other disseminated lesions beyond the skin, including in the lungs and liver. Because the patient was immunosuppressed, in accordance with previous literature, a combination therapy of clarithromycin, ethambutol, and rifampicin for 4 months was recommended. When no growth is observed on the Ogawa medium in cases of infection, it is essential to identify the infectious pathogen by genetic analysis.
龟分枝杆菌是一种罕见的非结核分枝杆菌，已被报道可引起免疫功能低下患者的播散性感染。由于龟分枝杆菌生长缓慢，在 Ogawa 培养基上难以形成菌落，因此需要进行遗传和分子分析来鉴定这种病原体。非结核分枝杆菌感染表现出各种皮肤表现。其中，已有罕见病例报告出现分枝杆菌假瘤。然而，目前尚无龟分枝杆菌引起皮肤假瘤的报道。本文报告了一例仅在皮肤病变中观察到的龟分枝杆菌感染引起的假瘤。患者正在服用 5 毫克泼尼松龙，并注意到右小腿有一个肿瘤。活检样本显示弥漫性梭形组织细胞和各种其他炎症细胞浸润，齐尔-尼尔森染色检测到分枝杆菌。由于 Ogawa 培养基上未形成菌落，因此进行了基因检测，通过 DNA 序列分析鉴定为龟分枝杆菌。除皮肤外，无其他播散性病变，包括肺部和肝脏。由于患者存在免疫抑制，根据以往的文献，建议采用克拉霉素、乙胺丁醇和利福平联合治疗 4 个月。如果在感染情况下 Ogawa 培养基上未观察到生长，通过遗传分析鉴定感染病原体至关重要。
