Inflammatory pseudotumor of the nasopharynx with spread along the trigeminal nerve

Inflammatory Myofibroblastic Tumor: Two Cases in Head and Neck Region

Previously described as inflammatory pseudotumor, inflammatory myofibroblastic tumors (IMT) are now considered as distinct tumors of specific histopathologic features. This rare mesenchymal tumor consists of spindle shaped fibroblasts associated with various amounts of inflammatory cells. Head and neck region, is an unusual site of involvement. In this article, we will introduce two separate cases with the diagnosis of IMT involving the nasopharynx and the temporal bone which are both rare locations of presentation. Inflammatory myofibroblastic tumor should be considered in the differential diagnosis list of every mass in head and neck region.

Imaging features, therapies, and outcomes of fibrosing inflammatory pseudotumor of the nasopharynx: A systematic review

BACKGROUND AND PURPOSE

Fibrosing inflammatory pseudotumor (FIP) of the nasopharynx is a rare nonneoplastic inflammatory lesion that is frequently mistaken for malignancy or infection. It is often misdiagnosed by radiologists as nasopharyngeal carcinoma or lymphoma, resulting in multiple biopsies and delays in diagnosis. The purpose is to understand trends in clinical presentation, imaging findings, treatment modalities, and patient outcomes of nasopharyngeal FIP.

METHODS

MEDLINE and EMBASE databases were queried for articles related to FIP of the nasopharynx. Articles that described cases of FIP involving the nasopharynx were selected. Studies that described inflammatory pseudotumor of the nasopharynx associated with known distinct pathologic entities were excluded.

RESULTS

A total of 19 articles describing 37 patients were included. MRI findings were reported in 32 patients. All cases demonstrated avid gadolinium enhancement. T2-weighted imaging characteristics were described or displayed for 21 patients: 95% demonstrated hypointensity compared to surrounding mucosa. Fluorodeoxyglucose (FDG) PET/CT findings were reported for 6 patients, all demonstrating mild FDG avidity.

CONCLUSIONS

Nasopharyngeal FIP is a histological diagnosis of exclusion that presents with facial pain and, often, cranial neuropathies. Relatively low T2-weighted MRI signal should inform the interpreting neuroradiologist to include FIP as a differential consideration for both the ordering provider and pathologist. Corticosteroid therapy is the most frequently employed therapy and results in partial or complete response in most patients. Radiation therapy and anti-inflammatory medications have also been reported to have potential therapeutic roles.

Fibrosing Inflammatory Pseudotumor Presenting as Cranial Neuropathy

We report two cases of biopsy-corroborated “fibrosing inflammatory pseudotumor” to illustrate that the entity, rarely described in the neurological literature, should be included in the differential diagnosis of either a cranial mononeuropathy or, certainly, in the case of progressive cranial neuropathies. A broad differential diagnosis arises in certain contexts. Early steroid treatment can be effective, and perhaps later-generation immune-modulating agents may confer further options, although there is no known definitive treatment.

A Rare Presentation of Inflammatory Myofibroblastic Tumor in the Nasolabial Fold

Inflammatory myofibroblastic tumor (IMT) is a benign lesion that occurs most frequently in the soft tissues and viscera. In the head and neck region, the tumor has been reported to occur in the orbit, tongue, nasopharynx, larynx, and paranasal sinuses and the central nervous system. Despite being a benign lesion, it exhibits infiltrative and destructive behaviours, making histopathological examination necessary to confirm the diagnosis. We report the case of a 38-year-old female presented with a right nasolabial fold mass, which was confirmed histologically to be an IMT. Surgical excision of the mass was achieved through a sublabial approach with an uneventful postoperative period. To the best of our knowledge, this is the first reported case of an IMT in the nasolabial fold.

Sinonasal Inflammatory Myofibroblastic Tumor with Anaplastic Lymphoma Kinase 1 Rearrangement: Case Study and Literature Review

Inflammatory myofibroblastic tumors (IMTs) are rare mesenchymal tumors initially described in the lung. About half of them exhibit expression of the ALK1 protein, generally resulting from a gene rearrangement. Paranasal sinus IMTs are extremely uncommon, and gene rearrangement of ALK1 is very rare in this localization. A 47-year-old woman presented with rapidly progressive vision loss in her left eye. Clinical and imaging work-up revealed a tumor invading the left ethmoidal and sphenoidal sinuses and extending into the nasal cavity, the orbit and the skull base. Complete tumor resection was performed using an endonasal approach. Pathological examination revealed a paranasal localization of IMT, positive for ALK1 immunostaining. FISH analysis showed an ALK1 gene rearrangement. This case illustrates the local aggressive potential for IMTs. Treatment is primarily surgical, but targeted therapies (crizotinib) might be a solution for ALK1 rearranged cases with a poor prognosis.

Discrepant lesion size estimated on T1- and fat-suppressed T2-weighted MRI: diagnostic value for differentiation between inflammatory pseudotumor and carcinoma of the nasopharynx

PURPOSE

Nasopharyngeal inflammatory pseudotumor (NIPT) is hard to differentiate from infiltrating nasopharyngeal carcinoma (NPC) on conventional magnetic resonance imaging (MRI). The purpose of this study is to determine whether discrepant lesion sizes estimated on T1- and fat-suppressed T2-weighted images can help distinguish between NIPT and NPC.

METHODS

We retrospectively reviewed MRI data of histologically proven 14 NIPTs and 18 infiltrating NPCs. We measured the area of the lesion on contrast-enhanced T1-weighted, unenhanced T1-weighted, and fat-suppressed T2-weighted images by placing the largest possible polygonal region-of-interest within the lesion at the same level. Using lesion size measured on contrast-enhanced T1-weighted image as the reference, we calculated and compared area ratio of T1 (ART1) and area ratio of T2 (ART2) between NIPTs and NPCs. For validation, we also undertook a double-blinded study by two reviewers and assessed the diagnostic performance and interobserver agreement.

RESULTS

For NIPTs, ART2 (median, 0.48; range, 0.18-0.97) was statistically significantly less than ART1 (median, 1.01; range, 0.80-1.99), while these values were not significantly different for NPCs. The interobserver agreement in differentiating between NIPT and NPC was good, with a sensitivity of 93% and a specificity of 83%-94%.

CONCLUSION

In contrast to NPCs, NIPTs appear smaller on fat-suppressed T2-weighted images than on T1-weighted images. This discrepancy in the lesion size estimated on T1-weighted and fat-suppressed T2-weighted images may provide a simple and consistent way to differentiate between NIPTs and NPCs on conventional MRI.