Solitary Neurofibroma of the Maxillary Sinus: A Rare Paranasal Tumor Case Study

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 Solitary Neurofibroma of the Maxillary Sinus: A Rare Paranasal Tumor Case Study

Introduction

Neurofibroma is a benign peripheral nerve sheath tumor, commonly associated with Neurofibromatosis Type I. However, solitary neurofibromas in the paranasal sinuses, especially the maxillary sinus, are exceedingly rare, with fewer than 100 cases reported globally. This column explores a rare case of a solitary neurofibroma involving the left maxillary sinus in a 56-year-old woman. It includes radiologic, clinical, and pathologic aspects, SEO-optimized medical insights, diagnostic differentials, and interactive medical quizzes based on the included images.

Clinical Presentation

A 56-year-old woman presented with a 4-week history of dull pain in the left neck and a palpable bean-sized mass. There were no constitutional symptoms such as fever, sore throat, or chest tightness. She had occasional cough with scant white sputum but no signs of acute infection.

Ultrasound examination initially revealed cervical lymphadenopathy (Figure 1), prompting further evaluation with chest CT and brain MRI. Subsequent imaging revealed a suspicious solid lesion in the left maxillary sinus, leading to a differential diagnosis that included benign and malignant neoplasms.

Radiologic Findings

Figure 1

Figure 1. Cervical ultrasound showing enlarged lymph node in the left neck with suspicious echogenicity.

The first radiologic clue was from a neck ultrasound, suggesting reactive or neoplastic lymphadenopathy.

Figure 2

Figure 2. Chest CT (lung window) showing an irregular nodular lesion in the left lower lobe.

A chest CT scan demonstrated an irregular nodular lesion in the left lower lung lobe, raising the question of metastasis or dual pathology.

Figure 3

Axial T1- and T2-weighted brain MR showing a 45 × 36 × 26 mm solid mass in the left maxillary sinus with intermediate intensity on T1 and heterogeneous hyperintensity on T2-weighted images.

The non-contrast brain MRI confirmed a solid lesion in the left maxillary sinus with:

  • T1WI: Hypointense

  • T2WI: Heterogeneously hyperintense

  • Fat-suppressed and DWI: Mild hyperintensity

Figure 4 (a–d)

Figure 4. Axial CT of the paranasal sinus shows a soft tissue mass with central punctate calcification. Contrast-enhanced CT shows mild heterogeneous enhancement (~5–10 HU increase) with maxillary sinus expansion and local bony erosion.

These CT findings were consistent with a solid mass in the left maxillary sinus, exhibiting bone remodeling and mild contrast enhancement, which suggested a slow-growing neoplastic lesion.

Differential Diagnosis

Differential considerations based on the radiologic appearance and clinical context included:

  • Inverted papilloma

  • Inflammatory granuloma

  • Metastatic lesion

  • Carcinoma

  • Neurofibroma (most likely)

Histopathologic evaluation ultimately confirmed the diagnosis of solitary neurofibroma.

Discussion

Epidemiology & Rarity

Solitary neurofibromas of the paranasal sinuses are extremely rare. Among less than 100 cases globally, most are single case reports. The majority occur in adults aged 30–70, with a female predominance.

Most maxillary neurofibromas are isolated lesions, with only ~10% linked to NF1.

Clinical Features

Symptoms are nonspecific, often mimicking sinusitis or benign cysts. Common findings include:

  • Facial fullness or pain

  • Nasal congestion or discharge

  • Epistaxis (rare)

  • Orbital invasion leading to proptosis or diplopia

  • Dental changes if the alveolar bone is involved

In this case, cervical pain and a palpable mass were the initial presentation.

Radiologic Considerations

Neurofibromas show the following on imaging:

  • CT: Soft tissue density with possible bony erosion, punctate calcification, and mild enhancement.

  • MRI: T1 hypointense to isointense; T2 heterogeneously hyperintense; DWI shows no restricted diffusion.

Treatment and Prognosis

The treatment of choice is surgical excision, with:

  • Minimal recurrence

  • No established role for chemotherapy or radiation

  • Excellent prognosis in isolated, non-NF1-associated tumors

Quiz

1. Which part of the paranasal sinus is primarily affected?

A. Left nasal mucosa
B. Left maxilla
C. Left nasal cavity
D. Left inferior turbinate
E. Nasal septum

2. What is the most likely diagnosis?

A. Inverted papilloma
B. Carcinoma
C. Inflammatory granuloma
D. Metastatic tumor
E. Neurofibroma

3. Is this neurofibroma associated with Neurofibromatosis Type I?

A. True
B. False

4. What is the best treatment for this condition?

A. Radiation therapy
B. Chemotherapy
C. Herbal medicine
D. Conservative therapy
E. Surgery

5. Which imaging feature supports a diagnosis of neurofibroma?

A. Homogeneous enhancement
B. Intense restricted diffusion
C. T2-weighted hyperintensity with bony remodeling
D. Large central necrosis
E. Calcified lymph nodes

Answer & Explanation

1. Answer: B. Left maxilla. Explanation: Imaging revealed a solid mass in the left maxillary sinus, expanding and eroding local bony walls.

2. Answer: E. Neurofibroma. Explanation: MRI and CT findings, along with histopathology, confirmed the diagnosis of a benign neurofibroma.

3. Answer: B. False. Explanation: Most solitary neurofibromas are not associated with NF1 and present as isolated lesions.

4. Answer: E. Surgery. Explanation: Complete surgical excision is curative and is the standard approach for localized paranasal neurofibroma.

5. Answer: C. T2-weighted hyperintensity with bony remodeling. Explanation: Heterogeneous T2 hyperintensity and expansile remodeling with mild enhancement are classic findings.

Learning Points

  • Solitary neurofibroma of the maxillary sinus is extremely rare, often misdiagnosed.

  • Imaging is crucial but non-specific; biopsy is essential for diagnosis.

  • These tumors usually demonstrate slow growth, bone erosion, and mild enhancement.

  • Surgery is the mainstay of treatment, with low recurrence rates.

References

[1] L. Azani, A. Ghanadan, and M. Sharifi, “Solitary neurofibroma of the maxillary sinus: A rare case report and review,” Iran J Pathol, vol. 13, no. 2, pp. 251–254, 2018.
[2] S. Ray, R. Chatterjee, and B. Dasgupta, “Neurofibroma of maxillary sinus: A rare paranasal presentation,” J Clin Diagn Res, vol. 10, no. 12, pp. MD01–MD03, 2016.
[3] M. S. Salemis, A. G. Karagkiouzis, and C. Gourgiotis, “Neurofibroma of the maxillary sinus,” Oral Surg Oral Med Oral Pathol Oral Radiol Endod, vol. 107, no. 5, pp. e33–e36, 2009.
[4] A. Yildirim et al., “Imaging features of neurofibroma involving paranasal sinus,” Clin Imaging, vol. 36, no. 3, pp. 195–198, 2012.
[5] T. Takano et al., “MRI features of solitary neurofibroma in the head and neck,” Radiat Med, vol. 20, no. 1, pp. 23–27, 2002.
[6] M. A. Mondal, A. Sarkar, and B. Das, “Solitary neurofibroma of the sinonasal tract,” J Laryngol Otol, vol. 118, no. 9, pp. 719–721, 2004.
[7] M. Yadav et al., “Solitary neurofibroma of nasal cavity: Imaging diagnosis and management,” Pol J Radiol, vol. 80, pp. 543–546, 2015.

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