Answer 1: D (Atypical carcinoid tumor)
Answer 2: D (All of the above)
A 50-year-old male complains of episodic flushing and tachycardia over the past few months. X-rays revealed a pulmonary mass. Above is an H&E from the lung.Comment: Primary pulmonary neuroendocrine tumors represent about 20% of all lung cancers. They are classified into four categories:
1. Typical carcinoid tumor
2. Atypical carcinoid tumor
3. Large-cell neuroendocrine tumor
4. Small-cell neuroendocrine tumor
The atypical carcinoids, such as the current example, have been the most difficult to classify. The presence of Chromogranin A or Synaptophysin identifies the tumor as neuroendocrine. Current recommendations suggest that mitotic rate (Ki-67) and p53 and ras mutations are useful prognostic indicators.
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Reference:
1. Gustafsson BI, Kidd M, Chan A, et al. Bronchopulmonary neuroendocrine tumors. Cancer. 2008 Jul 1;113(1):5-21. PubMed PMID: 18473355.
2. Przygodzki RM, Finkelstein SD, Langer JC, et al. Analysis of p53, K-ras-2, and C-raf-1 in pulmonary neuroendocrine tumors. Correlation with histological subtype and clinical outcome. Am J Pathol. 1996 May;148(5):1531-1541. PubMed PMID: 8623922.
3. Kobayashi Y, Tokuchi Y, Hashimoto T, et al. Molecular markers for reinforcement of histological subclassification of neuroendocrine lung tumors. Cancer Sci. 2004 Apr;95(4):334-341. PubMed PMID: 15072592.
4. Rekhtman N. Neuroendocrine tumors of the lung: an update. Arch Pathol Lab Med. 2010 Nov;134(11):1628-38. Review. PubMed PMID: 21043816.
