An 11-year-old boy presented with arthralgias, swollen knees, and finger clubbing of 2-year duration, signs and symptoms compatible with hypertrophic osteoarthropathy ( Fig. 1). He denied cough, chest pain, weight loss, or fever. His medical and family history were unremarkable. Physical examination only revealed digital clubbing and mucocutaneous pallor. A chest radiograph disclosed a large, round, well-defined, lobulated mediastinal mass (Fig. 2), and thoracic computed tomography (CT) disclosed a large, heterogeneous mass in the anterior mediastinum with no evidence of pleural, parenchymal, or chest wall invasion. Clubbing and hypertrophic osteoarthropathy have been reported in children with Hodgkin disease, thymoma, and other childhood malignant diseases [1][2][3][4]. Our working diagnoses therefore favored lymphoma or some form of intrathoracic cancer.Laboratory studies showed hypochromic, microcytic anemia (hemoglobin 8.1 g/dl, hematocrit 29%, mean corpuscular volume 56 fl, mean corpuscular hemoglobin 16 pg, mean corpuscular hemoglobin concentration 27 g/dl), thrombocytosis (862,000/mm 3 ), an increased erythrocyte sedimentation rate (105 mm/h), and polyclonal hypergammaglobulinemia (IgG 26.8 g/l).A CT-guided fine-needle aspiration cytology ruled out the possibility of a lymphoma and suggested either a thymoma or a teratoma. Serum levels of tumor markers (beta-human chorionic gonadotrophin, alpha-fetoprotein, and specific neurolase) were normal.A wide, left posterolateral thoracotomy was performed, disclosing a firm mass that seemed mediastinal in origin and intimately attached to the thymus and to a small portion of the left upper lobe. The tumor mass was totally resected (along with the entire thymus and a small tongue-like extension of the mass into the left upper lobe). The postoperative course was uneventful, and the patient was discharged on the seventh postoperative day.On gross examination, the lesion was a wellmarginated, lobulated, fleshy mass with a grayish-white cut surface on sectioning and with focal hemorrhagic areas, measuring 12 × 6 × 6.5 cm. Microscopically, the lesion showed spindle cells (arranged in an interlacing fascicular pattern) with oval vesicular nuclei, along with foamy histiocytes, plasma cells, and lymphocytes (Fig. 3). Immunohistochemical analysis revealed reactivity for vimentin, Factor XIII, alpha-1-antitrypsin, alpha-1-antichymotrypsin, and CD68, whereas antibodies against muscle-specific actin, CD34, Factor VIII-related antigen, and cytokeratin were nonreactive.The patient received a 6-week course of corticosteroid therapy postoperatively and 2 months later the arthralgias had disappeared, the digital clubbing had lessened significantly, and the laboratory parameters had completely resolved. Six months after surgery, the patient has no evidence of tumor recurrence and digital clubbing has disappeared.
DISCUSSIONInflammatory pseudotumor (also known as inflammatory myofibroblastic tumor, plasma cell granuloma, xanthogranuloma, fibrohistiocytoma, xanthomatous pseudotumor, an...
