Sinonasal squamous cell carcinoma

KERATINIZING SQUAMOUS CELL CARCINOMA (KSCC)

• these are rare and typically occur in elderly males. Can originate from inverted papillomas.

 • exhibit same histological features as conventional squamous cell carcinoma (SCC).

 • 5- year survival is 50– 60%.

NON- KERATINIZING SQUAMOUS CELL CARCINOMA (NKSCC)

 • these also typically occur in elderly males.

 • 30– 50% harbour high- risk HPV.

 • Most common sites are the maxillary sinus, lateral nasal wall, and nasal septum.

 • histologically expanding nests or ribbons of non- keratinizing squamous epithelium sometimes with papillae.

 • 5- year survival is 50– 60%. Not yet known if HPV confers a better survival.

Sinonasal adenocarcinomas

INTESTINAL- TYPE ADENOCARCINOMA (ITAC)

 • Marked male predilection and usually arise in the ethmoid sinus and nasal cavity. there is a well- recognized association with occupational exposure, particularly in wood workers.

 • Most occur in ethmoid sinus>nasal cavity>maxillary sinus.

 • histologically similar to adenocarcinomas of the gastrointestinal (GI) tract.

 • prognosis depends on grade and stage. 68% 5- year survival.

NON- INTESTINAL-TYPE ADENOCARCINOMA (non-ITAC)

 • No sex predilection and wide age range. No known aetiology.

 • tend to involve the ethmoid sinus and maxillary sinus.

 • histologically low- grade tumours have a papillary/ tubular pattern. ‘Back- to- back’ appearance of single layer of uniform cuboidal/ columnar cells.

 • high- grade tumours are more diverse with solid growth pattern.

 SALIVARY-TYPE ADENOCARCINOMA

 • have an equal gender incidence and mostly arise in the maxillary sinuses. the most common histological type is adenoid cystic carcinoma.

 Sinonasal undifferentiated carcinoma

 • a rare, but highly aggressive, malignancy arising in the sinonasal tract.

• presents with a large mass with bone destruction.

 • histology shows sheets of undifferentiated epithelial cells with high mitotic activity and necrosis. there are no glandular or squamous features.

• prognosis is poor (35% 5- year survival)

NUT carcinoma

 • poorly differentiated carcinoma with squamous differentiation defined by presence of nuclear protein in testis (NUT) gene rearrangement.

 • Median age 21 years and occurs in midline structures such as the nasal cavity and paranasal sinuses.

• 50% cases present with lymph node or distant metastases.

 • poor prognosis— median survival

Olfactory neuroblastoma

 • rare sinonasal malignancy or neuroectodermal origin arising from the olfactory epithelium.

 • even distribution across all ages.

 • presents with nasal obstruction, anosmia, and headaches.

 • histology shows lobules/ nests of closely packed, small, round, blue cells which may form pseudorosettes or true rosettes, which are surrounded by sustentacular cells.

• a histological grading system from 1 (low) to 4 (high) is used (after hyams).

 • the 5- year survival ranges from 40% to 90%, depending on the stage and grade.

Malignant melanoma

 • very rare sinonasal malignancy which presents with symptoms of nasal obstruction, discharge, and pain.

 • histology shows malignant melanocytes which can grow in a multitude of different patterns.

 • More likely to have a KIT mutation or amplification and less likely to have a BRAF mutation than cutaneous melanoma.

 • prognosis is generally poor.