atypical carcinoid tumor
Definition: Atypical carcinoid tumor shows either focal necrosis or mitosis numbering between 2-10/2mm2. Atypical carcinoid tumor may exhibit all of the growth patterns and cytologic features of typical carcinoid tumor.
Differential diagnosis
small-cell undifferentiated carcinoma
- Atypical carcinoid tumors have a distinctive microscopic pattern of nests, trabeculae, and ribbons of intermediate-sized, moderately pleomorphic cells that lack the nuclear molding and dense hyperchromasia of small-cell undifferentiated carcinoma. (#7180964#)
References
Atypical carcinoid tumor of the lung. A clinicopathologic study of 17 cases. Mills SE, Cooper PH, Walker AN, Kron IL. Am J Surg Pathol. 1982 Oct;6(7):643-54. PMID: #7180964#