Table of Contents
Definition / general | Terminology | Epidemiology | Sites | Etiology | Clinical features | Radiology images | Prognostic factors | Treatment | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Differential diagnosis | Additional referencesCite this page: Mannan R, Yuan S. Sinonasal undifferentiated carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/nasalsnuc.html. Accessed January 22nd, 2021.
Definition / general
- Rare, highly aggressive and clinicopathologically distinct malignancy of uncertain histogenesis
Terminology
- Sinonasal undifferentiated carcinoma (SNUC)
- Undifferentiated (anaplastic) carcinoma
Epidemiology
- Rare tumor, 85% smokers
- More common in men, occurs over a wide age range
- Median presentation in the sixth decade (Adv Anat Pathol 1999;6:317)
Sites
- Nasal cavity, maxillary antrum and ethmoid sinus are typically involved, either alone or in combination
- Usually presents as an extensively infiltrative disease involving multiple sites, including nasal cavity, one or more paranasal sinuses, orbit, skull base and brain
Etiology
- No known etiologic agents
- Typically negative for Epstein-Barr virus but there are reports of EBV RNA positivity in Asian (Am J Surg Pathol 1994;18:391) and Italian patients (Otolaryngol Head Neck Surg 1995;112:659) with SNUC
- Some cases have been reported to develop following radiation therapy for nasopharyngeal carcinoma (Am J Surg Pathol 2002;26:371)
Clinical features
- Patients typically present with multiple symptoms such as nasal obstruction, epistaxis, proptosis, visual disturbances, facial pain and symptoms of cranial nerve involvement
- Symptoms usually develop over a relatively short duration (weeks to months)
- This is a characteristic, though not pathognomonic feature of SNUC
Prognostic factors
- SNUC is a highly aggressive neoplasm
- Prognosis is poor, despite aggressive treatment, with a median survival of less than 18 months and a 5 year survival of less than 20% (Am J Surg Pathol 2002;26:371)
- Local recurrence is common and is a major cause of morbidity and mortality
- Metastatic disease occurs to cervical lymph nodes and to distant sites such as bone, lungs, brain and liver
Treatment
- Ideal therapy remains controversial
- Intensive multimodal therapy is usually employed, including surgery and adjuvant chemotherapy and radiotherapy
Gross description
- Usually > 4 cm
- Tend to be fungating, with ill defined borders and frequent invasion into adjacent structures
Microscopic (histologic) description
- Hypercellular proliferation, with trabecular, solid, ribbon, lobular and organoid growth patterns
- Composed of large, round to oval polygonal cells, with hyperchromatic to vesicular nuclei, inconspicuous to prominent nucleoli and a varying amount of eosinophilic cytoplasm and well defined to poorly defined cell borders
- There is increased mitotic activity, including atypical forms
- Tumor necrosis is often prominent, both confluent and individual cell necrosis
- Apoptosis is common
- Lymphovascular invasion and perineural invasion are common
- Neurofibrillary material and true neural rosettes are not identified
- Squamous or glandular differentiation is usually not present
Microscopic (histologic) images
Positive stains
- Pancytokeratin (AE1 / AE3), low molecular weight cytokeratin (CAM 5.2) and simple keratins (CK7, CK8, CK19)
- Staining is often strong and diffuse
- High Ki67 labeling index
- Positive for epithelial membrane antigen, neuron specific enolase or p53 in < 50% of cases
- Variably positive for p63
- Synaptophysin, chromogranin, S100 protein rarely positive
Negative stains
Electron microscopy description
- Rare dense core granules in individual cells
Differential diagnosis
- Mucosal melanoma
- Nasal type natural killer / T cell lymphoma
- Nasopharyngeal type undifferentiated carcinoma
- Olfactory neuroblastoma
- PNET / Ewing sarcoma
- Poorly differentiated adenocarcinoma
- Poorly differentiated squamous cell carcinoma
- Rhabdomyosarcoma
- Small cell undifferentiated neuroendocrine carcinoma
Additional references