Case of the Week

Background:

• Von Hippel-Lindau (VHL) syndrome is an inherited cancer syndrome characterized by an elevated risk of neoplasia including clear cell renal cell carcinoma, hemangioblastoma, and pheochromocytoma. Primary clear cell microcystic adenoma of the sinonasal cavity is a rare tumor subtype described with VHL that is considered benign but can show rapid growth and local recurrence, requiring regular surveillance. 

Clinical Presentation:

• Nasal obstruction and epistaxis

Key Diagnostic Features:

• Hypervascular mass with avid enhancement and flow void signal on T1WI and T2WI
• Mixed hyperintensity and hypointensity on T1-weighted and T2-weighted axial images
• Adjacent bone remodeling when tumor grows to a large size
• Benign appearance with a wide spectrum of growth rates
• Ancillary findings of VHL such as hemangioblastomas (as seen in our patient)

Differential Diagnoses:

• Sinonasal tumors: inverted papilloma, squamous cell carcinoma, and adenocarcinoma may have overlapping imaging appearance. However, the association with VHL and other tumor types can help raise suspicion of this specific tumor type in the nasal cavity.
• Juvenile nasopharyngeal angiofibroma:  Predilection for male adolescents and young adults between 14 and 25 years. Key feature is tumor being centered in the sphenopalatine foramen with involvement of the pterygopalatine fossa with anterior bowing of the posterior maxillary wall.

• Esthesioneuroblastoma: heterogeneous intermediate signal on T1WI and T2WI with greater degree of intracranial extension.
• Lymphoma: homogeneous intermediate signal on T1WI, homogeneous enhancement without flow signal void, diffusion restriction.

Treatment:

• Small lesions in asymptomatic patients are managed conservatively with regular imaging surveillance.
• Surgical resection is considered for larger or symptomatic tumors.