19 October 2005 – Case of the Week #24
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We thank Dr. Juan José Segura Fonseca, Departamento de Patología, Hospital San Juan de Dios, San José, Costa Rica for contributing this case. We invite you to contribute a Case of the Week by emailing NPernick@PathologyOutlines.com with microscopic images (any size, we will shrink if necessary) in JPG or GIF format, a short clinical history, your diagnosis and any other images (gross, immunostains, EM, etc.) that you have and that may be helpful or interesting. We will write the discussion (unless you want to), list you as the contributor, and send you a check for $35 (US) for your time after we send out the case. Please only send cases with a definitive diagnosis.
Case of the Week #24
A 43 year old man with a history of chronic sinusitis developed nasal obstruction. On examination, a unilateral polypoid mass was located in the right posterior nasal cavity in contact with the nasal septum. At excision, it measured 3 x 2 x 1 cm, was solid and soft, and had the gross characteristics of a nasal polyp. Microscopic examination shows a glandular, organoid, florid proliferation of tubular glands lined by ciliated, respiratory-type epithelium and goblet cells, without nuclear atypia (Figure 1, Figure 2, Figure 3). The stroma is edematous with inflammatory cells and eosinophils, similar to an inflammatory polyp (Figure 4).
Some glands have mucous metaplasia, similar to colonic glands (Figure 5). Invagination of the surface epithelium gives rise to ciliated tubular glands (Figure 6). Some seromucinous normal glands are interspaced with the tubular glands (Figure 7).
What is your diagnosis?
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Respiratory epithelial adenomatoid hamartoma of the nasal cavity
Hamartomas are defined as non-malignant malformations composed of excessive proliferation of one or more cellular components specific to a given tissue. In 1995, Wenig and Heffner reported 31 cases of what they called "Respiratory epithelial adenomatoid hamartoma of the sinonasal tract" (Ann Otol Rhinol Laryngol 1995;104:639). Within the nasal cavity, the most common site was the nasal septum along its posterior aspect. The median age was 58 years (range 27-82 years), and men were primarily affected. They arise in the setting of inflammatory polyps and their development is likely induced by an inflammatory process. Histologically, the lesions were characterized by a prominent tubular glandular proliferation lined by ciliated respiratory epithelium, originating from the surface epithelium. The basement membrane is thickened. No destructive growth is noted. Surgery is curative, and the lesions do not recur.
The differential diagnosis includes inflammatory polyps (fewer glands) and inverted schneiderian papillomas (usually hyperplastic squamous epithelium with only a few goblet cells and a thin basement membrane). More important is the differential diagnosis of sinonasal low grade adenocarcinoma, which usually demonstrates a back to back glandular pattern with nuclear atypia, prominent mitotic activity, desmoplastic stroma and perineural invasion.
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