Kaposi's sarcoma of the oral cavity
The purpose of this article is to review two cases of classic Kaposi's sarcoma (KS) and to discuss the current knowledge of pathogenesis, epidemiology, and clinical characteristics and treatment of the disease. KS is a malignant neoplasm of endothelial cell origin. Three different patterns have been identified: the classic form (older men from the Mediterranean basin), the endemic form of the African continent (children <10 years and older people), and the third pattern found in patients with AIDS.
The first case was a 72-year-old referred to the Clinic of Oral Medicine for evaluation of an asymptomatic intraoral lesion (present for four months). Clinical examination revealed a single tumor 2 cm in diameter involving the gingiva in the maxillary central incisor area. The tumor was pedunculated with a bluish-red mucosa. The patient was edentulous and had worn dentures for the past year. No extraoral lesions were seen. Biopsy showed endothelial hyperplasia (with atypical nuclei and mitotic figures). A diffuse cellular infiltrate consisting of Iymphocytes, hystocytes, and plasma cells was observed. A diagnosis of KS was made based on clinical, histological, and laboratory features. The patient was examined nine months later with no recurrence of the tumor.
The second case was an 85-year-old man with an asymptomatic intraoral lesion that had been present for the past 20 days. Clinically the lesions were multinodular and bluish-red, involving the border of the hard and soft palate. The patient had preexisting similar cutaneous lesions on the upper and lower extremities. Results from HIV and hepatitis B tests were negative. The patient's blood counts were within normal limits. Biopsy was taken from intraoral and cutaneous lesions. Both specimens showed common histopathologic features that were identical to case 1. The patient was diagnosed with KS.
Among 58 cases, 82% were males and 65% were > 60 years old. The most frequent site of the lesions was the palate (40%), followed by the tongue (14%), and lips (14%). Other lesions that could be considered during clinical differential diagnosis include pyogenic granuloma, hemangioma, melanoma, and erythroplakia. Classic KS has a rather indolent course and a fair to good prognosis. Several factors have been considered as the etiology of the disease. Some of these are genetic predisposition, viral infection, environmental influences, and immune disturbances. The African type supports the concept that KS may be of viral etiology. (Cytomegalovirus has been implicated, but data supporting its role is not definite.) An immune disturbance is supported by AIDS and other immunosuppressed patients. In the cases reported in this article, the authors were not able to determine any etiologic factor (patients did not reveal any other pathologic findings). In conclusion, histopathologic features of KS are identical in the three forms of the disease. It seems that the classic form is a rare one that appears to be more frequently expressed in male Mediterranean patients older than 60 years of age. [c.c.]
Markopoulos, A.K., P. Papanayotou, and G.Trigonidis, Quint Int, 25:415, 1994