recent WHO classification of primary sinonasal malignancies contains 44 distinct histopathologic entities [3]. Understandably, these cancers present a formidable challenge for both the surgeon and pathologist.In this article we present an unusual case of clear cell neoplasia of the paranasal sinuses found to be consistent with sinonasal renal cell-like adenocarcinoma (SNRCLA). The finding of clear cell neoplasia in a sinonasal specimen is rare but associated with a surprisingly wide differential diagnosis. When evaluating the differential diagnosis for a clear cell neoplasm of the sinonasal tract, an underlying renal cell carcinoma (RCC) must first be ruled out. RCC is the most common metastatic lesion to the nasal cavity and paranasal sinuses [4] and approximately 6-15% of patients with RCC will have metastatic deposits in the head and neck [5,6]. In addition to metastatic RCC, other diagnostic considerations for clear cell neoplasia in the paranasal sinuses include a clear cell variant of squamous cell carcinoma, melanoma, primary salivary clear cell carcinoma, metastatic clear cell thyroid carcinoma, clear cell predominant mucoepidermoid carcinoma, and SNRCLA.
Case ReportAn 80 year old female presented to our otolaryngology clinic with an asymptomatic right sinonasal mass. She reported a history of left sided acinic cell carcinoma treated at an outside institution with endonasal resection and adjuvant radiotherapy approximately eight years prior. Diagnostic nasal endoscopy revealed a large friable soft tissue mass arising from the lateral nasal wall near the axilla of the right middle turbinate. Imaging revealed a 3 cm tumor centered at the right nasolacrimal sac with extension superiorly to involve the nasal septum and dura of the anterior Abstract The differential diagnosis for clear cell neoplasms of the sinonasal tract is wide but critical to understand. In this paper, we describe a case of renal cell-like adenocarcinoma (SNRCLA) presenting as a paranasal sinus mass with clear cell morphology. The relevant literature is reviewed and the workup for clear cell neoplasms described. SNRCLA is a rarely encountered low grade glandular malignancy of the paranasal sinuses. Despite its morphologic mimicry of renal cell carcinoma, SNRCLA demonstrates a seromucinous phenotype and is associated with a favorable prognosis and low recurrence rates after surgical resection.