By Justin Bishop, MD, FASCP, and Lester D. Thompson, MD, FASCP
One of the most challenging diagnostic categories within tumors of the sinonasal tract is the small round blue cell tumors and spindled cell tumors. Biopsies are usually small and limited, resulting in considerable diagnostic difficulty for practicing surgical pathologists. These tumors share several overlapping histologic and immunophenotypic findings while also showing considerable variation within and between cases. Specific tumor site of origin, imaging findings, and clinical findings must be combined with the histology and pertinent ancillary studies if the correct diagnosis is to be reached.
At the ASCP 2018 Annual Meeting, we will present a session, WHO Knows the Nose? An Essential Guide to Sinonasal Tract Pathology, on Oct. 5. This session will emphasize a very practical approach to sinonasal tract pathology. In a case-based format, the session will serve as a review of classic sinonasal tract lesions with an emphasis on differential diagnosis (e.g., small round blue cell tumors, low-grade glandular proliferations, spindle cell lesions) and an update to the WHO Classification of sinonasal with an emphasis on newly-described entities.
Discrimination between neoplasms is critical as there are significant differences in therapy and overall outcome. It is important to have a well-developed differential diagnosis for this category of tumors, where each of the diagnoses is considered, evaluated, and either confirmed or excluded from further consideration. In an undifferentiated tumor, showing a small round blue cell morphology, using the mnemonic ‘MR SLEEP’ or ‘NOSE ALARM’ helps to highlight tumors to consider: melanoma, metastases, mesenchymal chondrosarcoma, rhabdomyosarcoma (alveolar), sinonasal undifferentiated carcinoma, squamous cell carcinoma (including NUT carcinoma), adenoid cystic carcinoma, small cell osteosarcoma, lymphoma, olfactory neuroblastoma) Ewing sarcoma/primitive neuroectodermal tumor, pituitary adenoma, and plasmacytoma.
A panel of pertinent immunohistochemistry studies, histochemistries and/or molecular tests should aid in reaching a diagnosis, especially when taking the pattern and intensity of reactions into consideration. Within the spindled cell tumor category, ‘BRASS for my Good Lab Practice’ is an awkward, but still all-encompassing mnemonic for various spindled cell tumors and reactions that can be seen. This particular topic will focus on a selection of these tumors, such as biphenotypic sinonasal sarcoma, rhabdomyosarcoma, respiratory epithelial adenomatoid hamartoma, angiofibroma, synovial sarcoma, solitary fibrous tumor, spindle cell squamous cell carcinoma, spindle cell mucosal melanoma, fibrosarcoma, fibromatosis, mycobacterial spindle cell tumor, glomangiopericytoma, leiomyosarcoma/leiomyoma and benign or malignant peripheral nerve sheath tumor and PEComa. It is always crucial to have as many differential diagnostic considerations available in your armamentarium in order to be able to reach the correct
One of the very nice things about the ASCP conferences is they are often a smaller, more intimate audience, which allows for the participants to easily interact with the faculty and discuss daily problems, or ask questions about difficult issues on the spot. This type of dynamic allows for all attending the conference to get the very best management and diagnostic criteria to apply in daily practice.
To learn about the ASCP 2018 Annual Meeting’s more than 250 hours of cutting edge education, click here.
Justin Bishop, MD, FASCP, and Lester D. Thompson, MD, FASCP, will lead a session, WHO Knows the Nose? An Essential (and Very Practical) Guide to the Sinonasal Tract Pathology, on Oct. 5 at the ASCP 2018 Annual Meeting, in Baltimore, MD.