A Giant Cell Tumor Arising from the Anterior Costal Arc in a Young Man Renata Fukamati Cavaguti 1 • Miriam Menna Barreto 1 • Paulo Marcos Valiante 1 • Gla ´ucia Zanetti 1 • Edson Marchiori 1 Received: 29 May 2015 / Accepted: 17 June 2015 Ó Springer Science+Business Media New York 2015 Case Report A 23-year-old man was admitted with complaint of a progressively growing mass in the right anterior chest wall associated with moderate recurrent pain. Clinical exami- nation showed a hardened, slightly tender mass with an approximate diameter of 8 cm fixed to the chest wall, in the mammary region. The overlying skin was normal. Chest computed tomography (CT) revealed a large lobulated mass arising anteriorly from the right third rib Fig. 1. Magnetic resonance imaging (MRI) demonstrated a hypointense heterogeneous mass on the chest wall, dis- placing the pectoral muscles anteriorly and the middle right lobe posteriorly Fig. 2. The tumor measured 14 9 11 cm 2 . An incisional biopsy was performed, and the pathological diagnosis was giant cell tumor (GCT) of the anterior costal arc Fig. 3. The tumor was excised Fig. 4, and the patient is receiving follow-up care. Two months after surgery, the patient remains asymptomatic, with no sign of recurrence. Discussion Typically, GCT affects mature bone and is most commonly seen in patients aged 20–40 years, with women affected twice as often as men [1–4]. The tumor has a predilection for the articular surfaces of tubular long bones, such as the distal femoral epiphysis and proximal tibial epiphysis around the knee joint (60 % of cases) [1, 3]. In a minority (1 %) of cases, GCT involves the rib, occurring most fre- quently on the posterior aspect of the costal arc. GCT of the anterior costal arc is very rare, making diagnosis chal- lenging [1, 3, 5]. On histopathological analysis, GCT shows the pre- dominance of two cell types: mononuclear stromal and multinucleated giant cells [4, 5]. The clinical presentation of GCT is nonspecific, and patients often present with moderate pain, swelling, and pathological fractures [1, 2, 4, 5]. Our case presented these most common findings. Radiographic features usually consist of an eccentric lytic & Edson Marchiori edmarchiori@gmail.com 1 Federal University of Rio de Janeiro, Rua Thomaz Cameron, 438. Valparaiso, Petro ´polis, Rio de Janeiro CEP 25685. 120, Brazil 123 Lung DOI 10.1007/s00408-015-9756-0