Primary combined small cell carcinoma of larynx with lateralized histologic components and corresponding side-specific neck nodal metastasis: report of a unique case and review of literature.

Combined small cell carcinoma (neuroendocrine) of the larynx has been rarely reported in the literature, and included in the current WHO classification. We hereby report an unusual case of combined carcinoma of the larynx; composed mainly of small cell neuroendocrine carcinoma nearly confined to the right side (mainly involving supraglottis extending to glottis) with synchronous minor in-situ and invasive squamous cell carcinoma component located on the left side of larynx (mainly glottis). Interestingly, this side-specific distribution of tumor was recapitulated in its metastatic nodal spread; so that right cervical lymph nodes showed only metastatic small cell carcinoma and left cervical lymph nodes only metastatic squamous cell carcinoma. To the best of our knowledge, the present case is the seventeenth reported case of a combined small cell carcinoma of larynx, second case in which individual tumor components were lateralized on either side of larynx, and the first case in which this side-specificity of tumor was reflected in its metastatic neck nodal spread. This report emphasizes the value of accurate pathologic diagnosis including diversity in differentiation and localization of laryngeal tumors, and underscores the need for thorough pathologic examination of bilateral laryngeal tumors. The pre-operative diagnostic yield of small cell carcinoma (pure or combined) can be enhanced by including deeper submucosal biopsies on laryngoscopy in all those cases in which the extent of disease on imaging is disproportionately larger than the apparent mucosal involvement on laryngoscopy. This approach can facilitate selection of neoadjuvant or palliative chemo-radiotherapy in large or unresectable tumors.