Kaposi sarcoma in an HIV-negative Tunisian patient: A rare cause of metatarsalgia

Kaposi sarcoma; Metatarsalgia; Osseous metastases; Magnetic resonance imaging Abstract Background: Kaposi sarcoma (KS) is an angioproliferative neoplasm that is commonly associated with human herpes virus-8 (HHV-8) and human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS). KS with osseous involvement is a rare occurrence, and is far more common in acquired immunodeficiency syndrome (AIDS)-related KS. Case presentation: We present a 32-year-old Tunisian man, HIV negative, who presented with a 4-year history of atraumatic mechanical metatarsalgia that progressively worsened with a limping gait. Physical examination revealed marked symmetrical forefoot lymphedema and a painful restricted left knee joint movement. Physical examination showed purple-blue plaques and nodules on the feet and ankles. Serologic tests for HIV and syphilis were negative. Plain radiography of the feet revealed numerous small lytic lesions. There were also scattered lytic lesions in the metaphysis of the proximal tibia and fibula. Osteolysis was predominantly left. Magnetic resonance imaging of the feet showed abnormal bone marrow signal of metatarsals and phalanges. Skin lesion biopsy yielded the diagnosis of Kaposi sarcoma. The disease was managed with chemotherapy including vinblastine. Conclusion: In a patient presenting with metatarsalgia without a commonly detected cause, it is mandatory to search for other lesions that may point to a rare diagnosis as KS which is famous for involvement of the metatarsal bone. 2016 Egyptian Society of Rheumatic Diseases. Publishing services provided by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).