A 48-year-old male immigrant with a painful foot mass

1Department of Internal Medicine, Texas Tech University Health Sciences Center; 2Amarillo Pathology Group; 3Section of Infectious Diseases, Department of Internal Medicine, Texas Tech University Health Sciences Center, Amarillo, Texas, USA Correspondence: Dr Faisal A Khasawneh, Section of Infectious Diseases, Department of Internal of Medicine, Texas Tech University Health Sciences Center, 1400 South Coulter Street, Amarillo, Texas 79106, USA. Telephone 806-354-5480, fax 806-354-5765, e-mail [email protected] CASE PRESENTATION A 48-year-old male immigrant from Myanmar (Southeast Asia) presented with a right dorsal foot mass that had been progressively enlarging for the past five years. The patient could not recall any precipitating events or trauma. It caused him mild pain, especially with ambulation. His medical history was significant for hypertension and tobacco use. He did not have diabetes or history of peripheral vascular disease. He immigrated to the United States approximately four years previously. On examination, there was no ulceration or draining sinuses. He had a strong posterior tibial pulse bilaterally and good capillary refill time; however, the right-sided dorsalis pedis pulse was not palpable. He had no evidence of neuropathy. There was no associated fever, lymphadenopathy or weight loss. Laboratory test results revealed a hemoglobin level of 157 g/L and white blood cell count of 5.4×109 cells/L without eosinophilia. Chemistry tests showed a creatinine level of 61.0 μmol/L, aspartate aminotransferase level of 33 U/L and alanine aminotransferase level of 19 U/L. Magnetic resonance imaging of the foot showed an enhancing soft-tissue mass overlying the metatarsal bones (Figure 1). There was no bone erosion or fluid collections. The patient underwent excisional biopsy of the lesion. A hematoxylin and eosin-stained section of the mass is shown in Figures 2 and 3. What is your diagnosis?