Difficulties in diagnosing angiomatoid fibrous histiocytoma of the head and neck region: A case report

Abstract

Background: Angiomatoid fibrous histiocytoma (AFH) is a rare, slow-growing soft tissue tumor. It appears mostly on the limbs and trunk in children and young adults. The biology of AFH remains unclear because of the small number of reported cases. Diagnostic testing does not provide definitive results. It has two clinical forms, that differ in terms of gene expression and clinical prognosis. It is important to inform the laboratory which specific gene testing is necessary. Here, we describe a case of rare AFH in the submandibular region using a full genetic panel.

Case summary: A 13-year-old boy who had been misdiagnosed in the past 6 mo by his dentist visited our clinic because of a lesion in the submandibular area on the right side. The lesion was homogeneous and painless upon palpation. No skin discoloration was observed. Due to the non-specific radiological picture computed tomography (CT), magnetic resonance imaging (MRI), cone-beam CT (CBCT), and ultrasound-guided biopsy were performed. A venous malformation was suspected on the MRI. None of the tests provided a definitive diagnosis. Owing to the non-specific radiological findings, the patient qualified for surgical treatment. The surgical procedure included an excisional biopsy. The diagnostic testing was extended using gene rearrangements. The most distinctive gene translocation in diagnosing AFH is within the EWS RNA-binding protein 1 (EWSR1)-CREB-binding protein. However, in this case, the diagnosis was confirmed by a rearrangement within the EWSR1 gene testing.

Conclusion: AFH in the submandibular location is rare, and surgical treatment with genetic evaluation defines AFH type that affects subsequent procedures.

Keywords: Angiomatoid fibrous histiocytoma; CREB-binding protein; Case report; Computed tomography; Fine-needle aspiration; Gene expression; Head and neck.

Figure 1

Computed tomography. A: Focal change on the right side of the submandibular space initially diagnosed as a venous malformation; B: Visible irregular outline of a moderately hyperintense area of 18 mm × 25 mm × 13 mm.

Figure 2

Fine needle aspiration at high magnification (400 ×, hematoxylin and eosin staining). A: Single bland cell with oval nucleus, smooth nuclear membranes, and conspicuous nucleolus; B: Spindle bland cells within an eosinophilic background.

Figure 3

A smooth contoured 3 mm defect in the cortical layer of the inner mandible on the right side near the border of the scan.

Figure 4

Histopathological diagnosis. A: Diffuse expression of smooth muscle actin. Excision, magnification 400 ×; B: Excision (400 ×, hematoxylin and eosin staining). Short spindled myoid and ovoid, histiocyte-like cells within a somewhat myxoid background.

Figure 5

Intraoperative picture. A: Intraoperative picture of submandibular, angiomatoid fibrous histiocytoma, tumor is marked with an arrow; B: Intraoperative picture of a destroyed external layer of the mandible, it is marked with an arrow; C: Intraoperative view of the second procedure, no AFH irregularities were found. Tissue scar are marked with arrows.

Figure 6

Magnetic resonance imaging before second surgical procedure. Just below the outline of the body of the mandible, a lesion suspected of a residual tumor mass of 4 mm × 8 mm × 4 mm is visible.

Figure 7

Proposed diagnostic and therapeutic path. AFH: Angiomatoid fibrous histiocytoma; CT: Computed tomography MRI: Magnetic resonance imaging.