Atypical Carcinoid Tumor of the Lung, Associated with Giant‐cell Transformation in Bone Metastasis

Abstract

A case of neuroendocrine lung tumor located beneath the pleura in a 71 year old woman is reported. At autopsy, the tumor was found to have metastasized to the bones and liver without involving the hilar lymph nodes. Histological‐ly, the tumor cells at the primary site and in the liver metastasis exhibited a carcinoid‐like organoid structure, whereas pleomorphic giant cells were noted in the bone metastasis. The argyrophilic tumor cells were immuno‐reactive for neuron specific enolase, chromogranin A, serotonin, calcitonin, calcitonin gene‐related peptide, gas‐trin‐releasing peptide, neuropeptide Y, gastrin, pancreatic polypeptide, glicentin, the alpha subunit of human cho‐rionic gonadotropin, keratin, epithelial membrane antigen, Leu M1 and carcinoembryonic antigen. Electron microscopy revealed abundant neurosecretory granules in the cytoplasm. This was considered to be a rare case of neuroendocrine lung tumor showing carcinoid like histology at the primary site and large‐cell transformation in bone metastasis.

Neuroendocrine Carcinomas of the Lung

“…Clinically, these tumors may be associated with carcinoid syndrome 31 and show a spectrum of cell differentiation that includes spindle cells and oncocytic and melanocytic features, among others. [32][33][34][35][36][37] However, other authors believe that the most accurate designation for these neoplasms is neuroendocrine carcinoma, which conveys the true nature of these tumors 22,38 and honors the previous classification of Gould et al, 19 in which atypical carcinoid is equivalent to well-differentiated neuroendocrine carcinoma. Important to mention about this designation of tumors is the lack of incorporation of the so-called tumorlet, which in reality may represent the true carcinoid (looks like carcinoma but is benign).…”

A Neuroendocrine Carcinoma of Undetermined Origin in a Dog

“…CK, SYN, NSE and CGA are usually expressed in neoplastic cells of NE cell tumors (carcinoids) that develop in the nasal cavity, lung or gastrointestinal tract 13 , 16 , 17 . In addition, such neoplastic cells sometimes express serotonin, substance P, VIP, neuropeptide Y and protein gene product 9.5 18 , 19 . Therefore, the positive immunoreactivity for CK, SYN, VIP and CGA in the present case strongly suggested that the NE cell was the origin of this tumor.…”