Case 22. (30 Mar. 1998)

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Diagnosis: Atypical Carcinoid

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   Atypical carcinoids have clinicopathologic features intermediate between the typical carcinoids and small cell carcinomas. Unlike typical carcinoids, the majority of atypical carcinoids are peripheral (50-100%), are associated with a history of cigarette smoking (83-94%), occur more often in men (2:1) and tend to occur in a slightly older age group (mean age in fifties to sixties).
   The histopathologic features that distinguish atypical carcinoid from typical carcinoid are: (1) increased mitotic activity ( an average of 10 mitoses per 10 high power fields); (2) greater cytological pleomorphism with larger, vesicular nuclei, larger, more frequent nucleoli and higher nuclear to cytoplasmic ratios; (3) increased cellularity and architectural irregularities; and (4) tumor necrosis.
   The radiographic features of atypical carcinoids of the lung are a round or ovoid shaped, 1.5 to 10 cm sized, contrast-enhancing, peripheral mass (21/32).  These masses showed slight to marked lobulation(15/21), and although some are smoothly bordered, but others exhibited a spiculated margin. Less commonly, they included multilobulated masses, a thin-walled cavity, lobar atelectasis without demonstrable mass.

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Return to Case 22. (30 Mar. 1998)

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