Lobular to Lobule: Metastatic Breast Carcinoma to Olfactory Neuroblastoma |
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Authors: | Kent M. Swimley Silvana Di Palma Lester D. R. Thompson |
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Affiliation: | 1.Department of Pathology & Medicine, Houston Methodist Hospital, Houston, TX USA ;2.Histopathology Department, Royal Surrey Hospital, Guildford, Surrey UK ;3.Southern California Permanente Medical Group, Department of Pathology, 5601 De Soto Avenue, Woodland Hills, CA 91365 USA |
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Abstract: | Tumor-to-tumor metastasis (TTM) is a rare, but well-described phenomenon occurring in patients with multiple synchronous or metachronous primary malignancies. Olfactory neuroblastoma (ONB) is a rare malignant, neuroectodermal sinonasal tract tumor that occurs within the ethmoid sinus involving the cribriform plate. Very few cases of ONB have been documented to metastasize to other primary malignancies, but the reverse scenario is exceptional. During an evaluation for anosmia, a right nasal polyp was identified on imaging and endoscopy in a 66-year-old woman, with a polypectomy performed. Histologic examination showed classical features of a low-grade olfactory neuroblastoma, but within the tumor were isolated epithelioid cells which were strongly pancytokeratin immunoreactive. Review of the clinical history revealed lobular breast carcinoma treated 10 years earlier. Further evaluation with immunohistochemistry showed strong and diffuse nuclear estrogen and progesterone receptor reactivity, along with GATA3. These results confirmed TTM of an invasive lobular breast carcinoma to ONB. By employing a limited immunohistochemistry panel for all small round blue cell tumors that includes pancytokeratin, p40, S100 protein, SOX10, synaptophysin, desmin, CD99, and CD45, one is able to more accurately diagnose the classical tumor types, while also showing potentially unusual tumor features or exceptionally rare events like metastatic lobular breast carcinoma to ONB. |
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Keywords: | Olfactory neuroblastoma Metastases Ethmoid sinus Tumor-to-tumor metastasis Lobular breast carcinoma Immunohistochemistry |
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