Pediatric sinonasal desmoid tumor

Desmoid fibromatosis-a diagnostic dilemma

PURPOSE

Desmoid fibromatosis in head and neck is infrequent and poses a significant challenge to the clinicians due to its non-specific characteristics.

METHODS

This case report focuses on a 69-year-old male who presented to a tertiary healthcare center in Karnataka, India with a swelling in the oral cavity.

RESULTS

Despite initial suspicions of malignancy based on clinical examination and findings on computed tomography imaging, subsequent histopathology and immunohistochemistry revealed an unexpected finding.

CONCLUSION

The case highlights the importance of clinical suspicion and histopathological evaluation as well as the need for greater awareness to facilitate early diagnosis and appropriate management of desmoid fibromatosis. We also present a literature review of varied presentations of desmoid tumors afflicting various subsites of the head and neck.

Desmoid Fibromatosis of Maxillary Sinus Masquerading as Nasal Polyp: A Case Report

Desmoid fibromatosis is also known as aggressive fibromatosis. It is a neoplastic monoclonal proliferation of fibroblasts, with an incidence of 2 to 4 per million per year. Its incidence peaks at 8 years of age and in the third/fourth decades of life. Here we discussed a patient in third decade of life who presented with unilateral nasal blockage with a picture suggestive of sinonasal polyposis on examination. On histopathology, he was diagnosed with Desmoid fibromatosis. Though a rare entity, Desmoid fibromatosis should be kept in mind as a differential diagnosis for appropriate patient management. As per our knowledge, in India this is the first documented case of desmoid fibromatosis arising from maxillary sinus.

Sinonasal Myxoma: A Distinct Entity or a Myxoid Variant of Desmoid Fibromatosis?

Sinonasal myxoma (SNM) is a rare benign mesenchymal tumor that arises in the sinonasal cavity or maxilla and almost exclusively affects young children. Currently, it is considered a specific entity, but its molecular characteristics have not been reported. Lesions diagnosed as SNM and odontogenic myxoma/fibromyxoma (OM/OFM) were identified from the participating institutions, and the clinicopathologic features were recorded. Immunohistochemistry for β-catenin was performed on all cases with available tissue. Next-generation sequencing (NGS) was performed on all SNM cases. Five patients with SNM were identified, including 3 boys and 2 girls with an age range of 20-36 months (mean: 26 months). The tumors were well-defined, centered in the maxillary sinus, surrounded by a rim of woven bone, and composed of a moderately cellular proliferation of spindle cells oriented in intersecting fascicles in a variably myxocollagenous stroma that contained extravasated erythrocytes. Histologically, the tumors resembled myxoid desmoid fibromatosis. Three tested cases showed nuclear expression of β-catenin. In 3 tumors, NGS revealed intragenic deletions of APC exons 5-6, 9 and 15, or 16, respectively, with concurrent loss of the other wild-type copy of APC, predicted to result in biallelic inactivation. The deletions were identical to those that occur in desmoid fibromatosis, and copy-number analysis raised the possibility that they were germline. In addition, one case showed possible deletion of APC exons 12-14, and another case exhibited a CTNNB1 p.S33C mutation. Ten patients with OM/OFM were identified, including 4 women and 6 men (mean age: 42 years). Seven tumors involved the mandible, and 3 the maxilla. Histologically, the tumors differed from SNM, and all cases lacked nuclear expression of β-catenin. These findings suggest that SNM represents a myxoid variant of desmoid fibromatosis that often arises in the maxilla. Because the APC alterations might be germline, genetic testing of the affected patients should be considered.

Desmoid-type fibromatosis of paranasal sinuses with intracranial extension in a child-acase-based review

PURPOSE

Desmoid-type fibromatosis (DF) is clonal fibroblastic proliferation that arises in the deep soft tissues, tends to reoccur, and is locally invasive. Desmoid-type fibromatosis of paranasal sinuses with intracranial extension is a rare condition that is even rarer in a small child. We aim to share with the reader our literature review, decision-making, and endoscopic endonasal operation procedure that combined gained us favorable results against this benign tumor with unpredictable natural history and disease course.

CASE REPORT

We describe the decision-making process in the management of a 3-year-old boy with a history of sudden vision loss and vomiting. MR showed an expansive well-delineated homogeneous tumor in the sphenoid sinus with intracranial extension and optic nerves compression. The diagnosis of a sporadic form of desmoid-type fibromatosis was made using genetic testing of tumor tissue. A total gross removal was carried out with endoscopic endonasal microsurgical approach. At a 3-month follow-up, the patient is without any signs of recurrance.

CONCLUSION

The treatment of children with desmoid-type fibromatosis requires a multidisciplinary approach by clinicians experienced with the management of pediatric cancer. While the desmoid-type fibromatosis is a benign, locally invasive tumor, observation should be the first step in the management. In case of life-threatening or symptomatic cases, operations that preserve function and structure should be the first choice for this benign tumor with unpredictable natural history and disease course.

Next-Generation Sequencing in the Diagnosis of Rare Pediatric Sinonasal Tumors

The diagnosis of desmoid fibromatosis or other spindle cell tumors in the sinonasal region is very rare in children and needs to be thoroughly confirmed with immunohistochemical and/or molecular tests. We report 2 patients with such rare tumors and describe the use of next-generation sequencing in their evaluation. A 3-year-old female had a 4.4-cm midline nasal cavity mass involving the bony septum and extending into the base of the skull bilaterally. The moderate cellular fibroblastic proliferation revealed areas of thick keloid-like collagen bands and other areas with myxoid edematous stroma. Deep targeted sequencing identified a novel G34V mutation in the CTNNB1 gene consistent with desmoid fibromatosis. An 11-month-old male infant presented with a right nasal mass that extended through the cribriform plate into the anterior cranial fossa and involved the right ethmoid sinus and adjacent right orbit. Histology revealed an infiltrative atypical fibrous proliferation with focal calcifications that was negative for CTNNB1 and GNAS mutations. A novel RET E511K variant was identified in the tumor and later was also found in the germline and hence rendered of unknown significance. Both cases highlight the utility of next-generation sequencing in the evaluation of pediatric sinonasal spindle cell tumors that may have overlapping pathologic features. Reporting of rare or novel variants in tumor-only sequencing should be cautiously evaluated in children and pairing with germline sequencing may be needed to avoid the pitfall of assigning uncommon variants.