Kaposi’s sarcoma (KS) is a peculiar tumor of viral etiology, with the HHV8 rhadinovirus playing a fundamental role in its development. Several epidemiological categories of KS have been identified, of which the sporadic, endemic, iatrogenic, and the epidemic are the main ones. Several histologic disease morphologies have been described, such as inflammatory, angiomatous, spindle cell, mixed, and the anaplastic (sarcomatous) subtypes. The skin of the limbs is most commonly affected, but any other organ or site may be involved. Microscopically KS may enter the differential diagnosis with several different entities, and for this purpose the immunohistochemical detection of the viral latent nuclear antigen-1 (LNA-1) may be crucial. Sporadic KS is usually benign, but rarely it may be aggressive. Anaplastic histology heralds an ominous course in any clinical context. We report a case of anaplastic retroperitoneal KS, occurring in an HIV-negative adult man. This patient presented with a huge left suprarenal mass, which was totally resected, and initially diagnosed as inflammatory leiomyosarcoma, because of the monomorphic spindle cell tumor morphology. After 12 years the tumor recurred locally as an unresectable mass, which was biopsied and examined. At the time of recurrence, the histologic slides of the primary tumor were reviewed, and the previous diagnosis was changed to that of atypical KS. Histologically the recurrent tumor showed both spindle cell and epithelioid appearances. Strongly diffuse HHV8/LAN-1 immunopositivity was documented in both tumors. The final diagnosis for the entire case was anaplastic KS. Then, the patient died in a few months.
*Department of Anatomic Pathology, School of Biomedical Sciences, Etromapmax Pole, Lesina (FG)
†Department of Medical and Surgical Sciences, School of Allergology and Clinical Immunology, University of Foggia
‡Department of Clinical Dermatology
§Anatomic Pathology Department
∥Department of Clinical Dermatology, Polyclinic of Foggia, Foggia
¶Department of Emergency Medicine, Polyclinic of Modena, Modena, Italy
#Department of Pathology, The Barzilai Medical Center, Ashkelon, Israel
M.B. was formerly at the Department of Pathology, IRCCS “Casa Sollievo della Sofferenza” Hospital, San Giovanni Rotondo, Foggia, Italy.
Presented in the “Soft Tissue and Bone Slide Seminar” at the 5th National Congress of the Italian Anatomic Pathology Society, September 21-25, 2010, Bologna, Italy.
The authors have no funding or conflicts of interest to disclose.
Reprints: Michele Bisceglia, MD, Via Santa Chiara, 9; 71043 Manfredonia, (FG), Italy (e-mail: firstname.lastname@example.org).
All figures can be viewed online in color at www.anatomicpathology.com.