Intestinal type sinonasal adenocarcinomas: a tale of two rare cases

Sinonasal adenocarcinoma is a rare malignancy arising from the glandular epithelium of the nasal cavity and paranasal sinuses, accounting for <1% all malignant sinonasal tumours. It commonly presents with symptoms such as nasal obstruction, epistaxis, and facial pain, often leading to late diagnosis. Here we are presenting cases of two young individuals with left nasal mass extending into cranial cavity and frontal sinuses. CT findings described them are infiltrative lesions with heterogenous contrast enhancement with involvement of cranium. Histopathology and PAS stain revealed atypical cells arranged in papillaroid to compact glandular growth pattern. At places, back-to-back arranged glands were also noted, composed of columnar cells having abundant eosinophilic cytoplasm and basally located nuclei with mild anisonucleosis. Relevant history was taken to exclude the possibility of colorectal metastasis; later CT abdomen was also done. Finally, IHC was performed on both cases which revealed positive staining for CK7, CDX2, SATB2 and negative staining for CK20, supporting the diagnosis. Thus, sinonasal adenocarcinoma should be considered in cases of persistent nasal symptoms. Early detection through imaging and histopathology aids in timely intervention.