J Oral Maxillofac Surg 60:951-954, 2002 Classic Kaposis Sarcoma of the Tongue: Case Report With Emphasis on the Differential Diagnosis Jorge S. Reis-Filho, MD,* Conceic ¸a ˜o Souto-Moura, MD,† and Jose ´ Manuel Lopes, MD, PhD‡ Kaposi's sarcoma (KS) is a well-known malignant vas- cular tumor first described under the term “idiopa- thisches multiples pigmentsarkom der Haut” (idio- pathic multiple pigmented sarcoma of the skin), by Kaposi, in 1872. 1 This initially rare neoplasm 2-4 has become one of the most frequent vascular sarcomas due to its high prevalence in immunocompromised patients, mainly in those with acquired immunodefi- ciency syndrome (AIDS). 2-4 Currently, there is strong evidence that KS is caused by the human herpes virus VIII (HHV-8). 2-5 Classically, KS have been classified as classic or Mediterranean, endemic or African, posttransplant, and epidemic or AIDS-associated KS. 2-4 In all of the clinical forms, the histopathologic and immunohisto- chemical features are similar. Moreover, HHV-8 DNA is found in almost every case of KS and in all of the clinical forms. 2-5 In the pre-AIDS era, oral KS used to be a very rare disease. 2-4 However, with the AIDS epidemic, its inci- dence increased to the point that in many instances it is the initial AIDS manifestation. 3 Oral KS in immuno- competent patients is rare and is often clinically mis- diagnosed as pyogenic granuloma or another benign vascular lesion. 6-8 Even rarer are examples of KS oc- curring in the tongue as an isolated tumor in a non- immunocompromised individual. 9 We herein report a recently diagnosed, unusual case of classic KS affect- ing the tongue of a nonimmunocompromised Euro- pean white elder and emphasize the main clinical and pathologic differential diagnosis. Report of a Case A previously healthy, 83-year-old woman presented with a 6-month history of oral bleeding and a slowly enlarging nodular lesion of the dorsal aspect of the tongue. Clinical and laboratory routine evaluation was unremarkable. No evidence of previous local or total body irradiation, trans- plantation, iatrogenic immunosuppression, blood transfu- sion, or AIDS was found in the patient’s medical history. HIV test results were also negative. Oral examination showed a blue-to-purplish, nodular, ul- cerated lesion on the midline dorsal aspect of the tongue measuring 1.2  1.0  1.0 cm. Clinical diagnostic impres- sion was pyogenic granuloma or angioma of the tongue. An excisional biopsy was carried out. The gross specimen con- sisted of a 1.8-  1.5-  1.0-cm ellipse of oral mucosa exhibiting a nodular and partially ulcerated surface, measur- ing 1.2 cm in its maximum diameter. Histologic examination showed a dome-shaped, ulcer- ated, nonencapsulated, and infiltrative neoplasm (Fig 1) composed of uniform but atypical spindle cells arranged in intersecting fascicles. The spindle cells showed ill-defined, eosinophilic cytoplasm, and plump oval hyperchromatic nuclei with distinct nucleoli (Fig 2). Intracellular lumen containing red blood cells and eosinophilic 0.4- to 10-m eosinophilic globules (Fig 2, inset) were observed in the cytoplasm of the neoplastic cells. Between the spindle cell component, small jagged vessels and slit-like vascular spaces containing extravasated red blood cells were ob- served. The mitotic index of the spindle cells was high, with 58 mitosis per 10 high-power fields (1 mm 2 ). A large num- ber of plasma cells and occasional mature lymphocytes were also seen (Fig 2, inset). Immunohistochemical analysis was performed using the streptavidin-biotin-peroxidase technique with heat-induced antigen retrieval using antibodies raised against vimentin (monoclonal, 1:50; Dakopatts, Glostrup, Denmark), desmin (monoclonal, 1:30; Dakopatts), CD31 (1:5; Dakopatts), cy- tokeratin AE1/AE3 (1:30; Biogenex, San Ramon, CA), and S-100 protein (1:700; Dakopatts). The neoplastic spindle cells showed strong cytoplasmic reactivity for vimentin and membranous positivity for CD31 (Fig 3). A diagnosis of nodular stage of KS was made. The patient was discharged and remains free of disease during the past month. Discussion KS is a multicentric malignant vascular neoplasm that has been the subject of great interest in the past 20 years due to its frequent association with AIDS and posttransplantation immunosuppression. 2-5 Regard- *PhD Student, Institute of Molecular Pathology and Immunol- ogy, University of Porto (IPATIMUP), Porto, Portugal. †Consultant Pathologist, Department of Pathology, Medical Fac- ulty, University of Porto and Hospital Sa ˜o Joa ˜o, Porto, Portugal. ‡Associate Professor, Institute of Molecular Pathology and Im- munology and Department of Pathology, Medical Faculty, Univer- sity of Porto (IPATIMUP) and Hospital Sa ˜o Joa ˜o, Porto, Portugal. Address correspondence and reprint requests to Dr Lopes: IPA- TIMUP, R. Roberto Frias, S/N, 4200 Porto, Portugal. © 2002 American Association of Oral and Maxillofacial Surgeons 0278-2391/02/6008-0020$35.00/0 doi:10.1053/joms.2002.33871 951