From a pathology perspective, an endolymphatic sac tumor needs to be separated from metastatic renal cell carcinoma, metastatic thyroid papillary carcinoma, middle ear adenoma, paraganglioma, choroid plexus papilloma, middle ear adenocarcinoma, and ceruminous adenoma. Management
Wide excision is the treatment of choice, although attempting to preserve hearing. Based on the anatomic site, it is difficult to completely remove, and so while there is a good prognosis, recurrences or persistence may be seen. There is no metastatic potential. Patients who succumb to the disease, usually do so because of other tumors within the von Hippel-Lindau complex rather than from this tumor. Surgery is the primary treatment modality, but in some rare instances adjuvant radiation therapy may be used. Epidemiology
This is a very rare tumor, since only about 1 in 35,000 to 40,000 people have VHL, of whom about 10% have endolymphatic sac tumors. Patients usually present in the 4th to 5th decades without an gender predilection. The tumor involves the endolymphatic sac, a portion of the intraosseous inner ear of the posterior petrous bone. References
Further reading
Lester D. R. Thompson; Bruce M. Wenig (2011). Diagnostic Pathology: Head and Neck: Published by Amirsys. Hagerstown, MD: Lippincott Williams & Wilkins. pp. 7:64–67. ISBN 978-1-931884-61-7.
Rituximab may have good activity against MCL as a single agent, but it is typically given in combination with chemotherapies, which prolongs response duration. There are newer variations on monoclonal antibodies combined with radioactive molecules known as radioimmunotherapy (RIT). These include Zevalin and Bexxar. Rituximab has also been used in small numbers of patients in combination with thalidomide with some effect. In contrast to these antibody-based passive immunotherapies, the field of active immunotherapy tries to activate a patients immune system to specifically eliminate their own tumor cells. Examples of active immunotherapy include cancer vaccines, adoptive cell transfer, and immunotransplant, which combines vaccination and autologous stem cell transplant. Though no active immunotherapies are currently a standard of care, numerous clinical trials are ongoing. Targeted therapy
Two Bruton tyrosine kinase inhibitors (BTKi), one In November 2013, ibrutinib (trade name Imbruvica, Pharmacyclics LLC) and in October 2017, acalabrutinib (trade name Calquence, AstraZeneca Pharmaceuticals LP) were approved in the United States for treating MCL. Other targeted agents include the proteasome inhibitor bortezomib, mTOR inhibitors such as  temsirolimus, and the P110δ inhibitor GS-1101.In November 2019, zanubrutinib (Brukinsa) was approved in the United States with an indication for the treatment of adults with mantle cell lymphoma who have received at least one prior therapy. Gene therapy
Brexucabtagene autoleucel (Tecartus) was approved for medical use in the United States in July 2020, with an indication for the treatment of adults with relapsed or refractory mantle cell lymphoma.