Typical Carcinoid (TC) comprise 1-2% and Atypical Carcinoid
(AC) comprise 0.1-0.2% of all pulmonary tumors, whereas small cell lung carcinoma (SCLC) and Large Cell Neuroendocrine Carcinoma (LCNECs) make up 20% and 1.6-3%, respectively
Hence, diagnosis of thymic atypical carcinoid
was considered with the positivity for synaptophysin and chromogranin along with CK7 positivity (Figure 5).
The recurrence rate for typical carcinoid is lower (3.6%) than that of atypical carcinoid
CAPNCI uses four general categories for neuroendocrine tumors of the uterine cervix, typical (classical) carcinoid tumor, atypical carcinoid
tumor, large cell neuroendocrine carcinoma, and small (oat) cell carcinoma .
Cueto et al., "Atypical carcinoid
tumours of the lung: prognostic factors and patterns of recurrence," Thorax, vol.
Depending on the location of the NET (foregut, hindgut, and pulmonary) other hormones can predominate in systemic circulation resulting in an atypical carcinoid
syndrome with variant clinical symptoms .
WHO (2005) classified neuroendocrine tumor (NET) of the larynx into 4 types: (1) typical carcinoid, (2) atypical carcinoid
(AC), (3) small cell carcinoma, neuroendocrine type, and (4) combined small cell carcinoma, neuroendocrine type, with nonsmall cell carcinoma .
Neuroendocrine neoplasms of the larynx encompass five separate tumors: paraganglioma, typical carcinoid, atypical carcinoid
, small cell carcinoma, and large cell neuroendocrine carcinoma.
Atypical carcinoidis based upon four elements: a morphological base, number of mitoses less than 2 per 10HPFs, absence of necrosis and dimension less than 0.5 cm; while an atypical carcinoid
shows carcinoid morphology with number of mitoses greater than 2 and less than 10 per 10 HPFs and areas of coagulative necrosis.3 The histopathology report of our patient showed approximately 1 mitosis/HPF which favoured a diagnosis of typical carcinoid.
(2-10 mitoses/10 HPF, with necrosis) has an intermediate behavior .
We present the case of an atypical carcinoid
tumor of lung origin metastasizing to a known pituitary adenoma.