Logani S, Lucas D R, Cheng J D, Ioachim H L, Adsay N V
Department of Pathology, Harper Hospital, Karmanos Cancer Institute and Wayne State University, Detroit, Michigan 48201, USA.
Am J Surg Pathol. 1999 Jun;23(6):656-61. doi: 10.1097/00000478-199906000-00004.
Patients infected with HIV often have unusual manifestations of common infections and neoplasms. One such example is "mycobacterial pseudotumor," an exuberant spindle cell lesion induced in lymph nodes by mycobacteria. Kaposi sarcoma also produces a spindle cell proliferation in lymph nodes of HIV-positive patients. These two entities must be differentiated from one another because of differences in treatment and prognosis. We report here, however, three cases of intranodal Kaposi sarcoma with simultaneous mycobacterial infection, the occurrence of which has not been clearly documented. For comparison, we also studied three cases of mycobacterial pseudotumor, of which 14 cases have been described to date. There was considerable histologic overlap between these two lesions. Acid-fast bacilli were present in all cases, predominantly in the more epithelioid histiocytes in the cases of Kaposi sarcoma, and in spindle and epithelioid cells in the cases of mycobacterial pseudotumor. The morphologic features that favored Kaposi sarcoma over mycobacterial pseudotumor were the prominent fascicular arrangement of spindle cells and slitlike spaces, the lack of granular, acidophilic cytoplasm, and the presence of mitoses. Immunohistochemistry was a reliable adjunct study in the differential diagnosis, as the spindle cells in mycobacterial pseudotumor were positive for S-100 protein and CD68 whereas those of Kaposi sarcoma were CD31- and CD34-positive but negative for S-100 protein and CD68. Awareness that Kaposi sarcoma may coexist with mycobacterial infection in the same biopsy specimen is important because these lesions may be misdiagnosed as mycobacterial pseudotumor. The clinical impact of distinguishing between Kaposi sarcoma with mycobacteria and mycobacterial pseudotumor is significant because the presence of Kaposi sarcoma alters treatment and prognosis.
感染艾滋病毒的患者常有常见感染和肿瘤的异常表现。一个例子是“分枝杆菌假瘤”，这是由分枝杆菌在淋巴结中诱导产生的一种旺盛的梭形细胞病变。卡波西肉瘤在艾滋病毒阳性患者的淋巴结中也会产生梭形细胞增殖。由于治疗和预后不同，这两种病变必须相互鉴别。然而，我们在此报告三例同时伴有分枝杆菌感染的淋巴结内卡波西肉瘤病例，其发生情况尚未有明确记录。为作比较，我们还研究了三例分枝杆菌假瘤病例，迄今为止已描述了14例。这两种病变在组织学上有相当多的重叠。所有病例中均存在抗酸杆菌，在卡波西肉瘤病例中主要存在于较多的上皮样组织细胞中，而在分枝杆菌假瘤病例中存在于梭形细胞和上皮样细胞中。相较于分枝杆菌假瘤，支持卡波西肉瘤的形态学特征为梭形细胞显著的束状排列和裂隙样间隙、缺乏颗粒状嗜酸性细胞质以及有丝分裂的存在。免疫组织化学在鉴别诊断中是一项可靠的辅助研究，因为分枝杆菌假瘤中的梭形细胞对S - 100蛋白和CD68呈阳性，而卡波西肉瘤的梭形细胞对CD31和CD34呈阳性，但对S - 100蛋白和CD68呈阴性。认识到在同一活检标本中卡波西肉瘤可能与分枝杆菌感染共存很重要，因为这些病变可能被误诊为分枝杆菌假瘤。区分伴有分枝杆菌的卡波西肉瘤和分枝杆菌假瘤的临床意义重大，因为卡波西肉瘤的存在会改变治疗和预后。
