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Int J Clin Exp Pathol 2013;6(5):957-961

Case Report
Carcinoid tumor of the lung with massive ossification: report of a case showing the
evidence of osteomimicry and review of the literature

Hiroyoshi Tsubochi, Shunsuke Endo, Yoshinao Oda, Yoh Dobashi

Departments of Thoracic Surgery and Pathology, Saitama Medical Center, Jichi Medical University, Saitama, Japan; Department of Anatomic
Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan

Received March 20, 2013; Accepted April 6, 2013; Epub April 15, 2013; Published May 1, 2013

Abstract: Carcinoid tumor is one of the commonly encountered primary pulmonary neoplasms. Although it has been known to be
accompanied by calcification and/or ossification, presentation with a large ossified mass is rare. We describe here the case of a 29-year-old
female with the radiological finding of a single bony nodular lesion. Pathological examination of the surgically resected specimen led to the
diagnosis of carcinoid tumor of the lung with massive ossification. Although histological features showed the tumor of low grade malignancy,
subcarinal and right hilar lymph nodes were found to be positive for metastasis. Further immunohistochemical analysis revealed that the tumor
cells expressed the osteogenic inducer protein, bone morphogenic protrein-2 [BMP-2] and osteoblastic marker protein, osteocalcin. We
interpreted this to mean that the carcinoid tumor cells had acquired an osteoblastic phenotype and had subsequently developed marked
intratumoral ossification. The relevant literature is reviewed and possible mechanisms of tumor-related osteogenesis are discussed.

Keywords: Carcinoid tumor, osteomimicry, bone morphogenic protein, osteocalcin

Address correspondence to: Dr. Shunsuke Endo, Department of Thoracic Surgery, Saitama Medical Center, Jichi Medical University, 1-847,
Amanuma, Omiya, Saitama, 330-8503, Japan. Phone/Fax: 81-48-648-5188; E-mail: tcvshun@jichi.ac.jp