Pyogenic granuloma-like Kaposi's sarcoma

Abstract

A 30-year-old man presented to the primary care clinic in June, 2015, with a 3 month history of a painful, foul-smelling mass between the second and third toes of his right foot that had been slowly increasing in size. The mass had begun as a small nodule and had originally been treated with antibiotics for presumed infection without success. On examination he had a red, fi rm mass about 3 cm diameter growing from the lateral aspect of the second toe (fi gure), which was tender to palpation and had a small amount of seropurulent discharge. Its appearance was suggestive of pyogenic granuloma with secondary infection. On questioning, the patient denied any medical or surgic al history, or tingling or numbness in the toes. A radiograph showed a soft tissue mass without extension into the bone. The patient was referred for surgical resection of the mass, at which time he admitted to a 5 year history of HIV. He had been off highly active antiretroviral therapy (HAART) for 2 years because of non-compliance and insurance issues. Histological examination of the resected mass showed nodules of spindle cells mixed with red blood cells; tumour cell immunohistochemistry was positive for CD34 and human herpesvirus (HHV-8), consistent with Kaposi’s sarcoma. Microscopy also showed colonies of Gram-positive cocci suggesting secondary infection. Further history and examination showed no other skin changes suggestive of Kaposi’s sarcoma. We diagnosed pyogenic granuloma-like Kaposi’s sarcoma. The patient was restarted on HAART and has needed no further treatment. Kaposi’s sarcoma is a vascular tumour caused by HHV-8. Although it is the most common neoplasm in patients with HIV/AIDs, it is quite rare (prevalence about 2% in patients with HIV/AIDS in USA). Pyogenic granuloma-like Kaposi’s sarcoma is a rare variant of Kaposi’s sarcoma. Lesions are superfi cial and protrude from the skin. Superimposed ulceration and secondary infection can give the appearance of pyogenic granuloma, and diagnosis of pyogenic granuloma-like Kaposi’s sarcoma can be challenging because it has histological features of both pyogenic granuloma and Kaposi’s sarcoma. Diagnosis is made by positive immunohistochemistry staining for CD34 and HHV-8. Kaposi’s sarcoma can present in diff erent forms, from classic purple rash to lesions that mimic diff erent skin disorders, such as pyogenic granuloma. Clinicians should maintain a high level of suspicion and seek early tissue diagnosis so as not to miss Kaposi’s sarcoma, especially in HIV-positive patients.