A CASE REPORT ON A RARE CASE OF INTESTINAL-TYPE SINONASAL ADENOCARCINOMA INVOLVING THE MAXILLA amal.sampang@gmail.com

PE039

A CASE REPORT ON A RARE CASE OF INTESTINAL-TYPE SINONASAL ADENOCARCINOMA INVOLVING THE MAXILLA

1

Philippines

Poster Exhibition only

Sinonasal adenocarcinomas are rare, comprising less than 1% of head and neck malignancies. Intestinal-type adenocarcinoma (ITAC), often linked to occupational exposures, primarily affects males aged 50–70. These tumors are typically diagnosed late due to nonspecific presentations and complex anatomic locations, especially when arising from the maxillary sinus.

A 62-year-old male with a 32-year history of a right preauricular mass presented with a progressively enlarging right maxillary lesion. Craniofacial CT revealed a heterogeneously enhancing soft tissue mass with an adjacent zygomatic nodule, both suspicious for malignancy. The patient underwent right selective neck dissection (levels Ib–III), superficial parotidectomy, and subtotal maxillectomy with en bloc resection of overlying skin. Frozen sections guided margin status. Reconstruction was performed using a platysma myocutaneous flap. Postoperative course and outpatient follow-up were documented.

Histopathology confirmed intestinal-type sinonasal adenocarcinoma with papillary features, showing lymphovascular and perineural invasion. The parotid lesion was benign. Postoperatively, the patient experienced transient right facial nerve paresis but recovered without major complications and was discharged on postoperative day 4. At follow-up, wound healing was satisfactory with partial improvement in nerve function. The patient was referred for adjuvant radiotherapy in line with guidelines for high-risk ITAC.

This case highlights an unusual presentation of maxillary ITAC with a long-standing benign-appearing mass. It underscores the importance of early imaging and biopsy in persistent facial lesions. Multidisciplinary management, including oncologic resection and tailored reconstruction, is essential for optimal outcomes in sinonasal malignancies.