Pigmented spindle cell carcinoid tumour of the thymus with ectopic adrenocorticotropic hormone secretion: report of a rare variant and differential diagnosis of mediastinal spindle cell neoplasms.

Abstract

AIMS:

A variety of histological variants of thymic carcinoid tumour have been described. A rare case of pigmented spindle cell carcinoid tumour of the thymus is documented and compared with the reported cases of thymic pigmented carcinoid tumour in the literature, with a discussion of the differential diagnosis of spindle cell tumours of the mediastinum.

METHODS AND RESULTS:

A thymic tumour with ectopic adrenocorticotropic hormone (ACTH) secretion was resected from a 24-year-old man suffering from Cushing's syndrome. Histological, immunohistochemical, and ultrastructural studies revealed an ACTH-producing spindle cell carcinoid tumour harbouring pigmented melanocytes. Among four thymic pigmented carcinoid tumours reported before, only one was similar to the present case by being also an ACTH-secreting pigmented spindle cell thymic carcinoid tumour. The clinicopathological features of this tumour distinguish it from a spindle cell thymoma, spindle cell thymic carcinoma, and other mediastinal spindle cell tumours.

CONCLUSIONS:

This case illustrates an extremely rare variant of thymic carcinoid tumour exhibiting a spindle cell morphology and harbouring pigmented melanocytes. Awareness of this histological variant is important in the differential diagnosis of spindle cell tumours of the mediastinum.

• Authors: T-t Kuo
• Journal: Histopathology (Histopathology) Vol. 40 Issue 2 Pg. 159-65 (Feb 2002) ISSN: 0309-0167 [Print] England
• PMID: 11952860 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers, Tumor
• Adrenocorticotropic Hormone

Topics

• Adrenocorticotropic Hormone (metabolism)
• Adult
• Biomarkers, Tumor (metabolism)
• Carcinoid Tumor (complications, metabolism, pathology, surgery)
• Carcinoma (pathology)
• Cushing Syndrome (complications, pathology)
• Diagnosis, Differential
• Humans
• Immunoenzyme Techniques
• Male
• Melanocytes (metabolism, pathology)
• Sarcoma (pathology)
• Secretory Vesicles (ultrastructure)
• Thymoma (pathology)
• Thymus Neoplasms (complications, metabolism, pathology, surgery)
• Tomography, X-Ray Computed