atypical carcinoid

atypical carcinoid

An intermediate form of neuroendocrine tumour between low-grade malignant (typical carcinoid) and high-grade small cell carcinoma.

Prognosis
Nodal metastases in 70% (vs. 5% for carcinoids); 5-year survival is 60%.

atypical carcinoid

An intermediate form of neuroendocrine tumor between low-grade malignant–typical carcinoid and high-grade small cell carcinoma. See Carcinoid, Small cell carcinoma.
References in periodicals archive ?
SCLC/NET Study highlights In an oral presentation today, researchers presented molecular profiling results from a large cohort of 607 lung tumor samples, consisting of 375 SCLC samples and 232 samples from lung NETs (including carcinoid, atypical carcinoid, and large-cell NETs).
We present the case of an atypical carcinoid tumor of lung origin metastasizing to a known pituitary adenoma.
We describe what we believe is the first reported case of an atypical carcinoid tumor, or any other type of neuroendocrine carcinoma, of the uvula.
The 2004 World Health Organization (WHO) classification recognizes 4 major types of lung neuroendocrine tumors (NETs): typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC), and small cell lung cancer (SCLC).
An atypical carcinoid tumor secreting 5-hydroxytryptophan.
An intermediate category, atypical carcinoid (AC), is used to designate tumors with features between those of typical carcinoids (TC) and high-grade neuroendocrine carcinomas (SCLC and LCNEC).
While the term atypical carcinoid is not well defined for gastrointestinal NETs, the AJCC Cancer Staging Manual2 recommends using this term for appendiceal NETs with a mitotic count of 2 to 10 mitoses per 10 HPFs and/or focal necrosis.
The time-honored classification scheme divides these tumors into 3 types, including carcinoid tumor, atypical carcinoid tumor, and small cell carcinoma.
Further immunohistochemical analysis with neuroendocrine markers stained strongly positive for chromogranin A and neuron-specific enolase, and the lesion was designated as an atypical carcinoid tumor (figure 1, B).
Pulmonary neuroendocrine tumors are relatively common and traditionally divided into 4 major categories: typical carcinoid (TC), atypical carcinoid (AC), small cell carcinoma (SC), and undifferentiated large cell neuroendocrine carcinoma (LC).
1,2,6) Their vascularity, the presence of amyloid, and positive calcitonin staining have led some to confuse atypical carcinoid with medullary carcinoma of the thyroid.

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