Arthroscopic Excision of Intra-articular AHRR-NCOA2- positive Angiofibroma of Soft Tissue of the Knee: A Case Report

Cervical angiofibroma of soft tissue: A rare case report with literature review

RATIONALE

Angiofibroma of soft tissue (AFST) is a rare benign fibrous tumor recently included in the 2020 WHO classification of soft tissue and bone tumors. Currently, there are limited reports on AFST, and pathologists lack sufficient understanding of its clinical and pathological characteristics. There is scarce literature available on AFST in the cervical region.

PATIENT CONCERNS

We presented a case of a 49-year-old woman who was admitted to our hospital for emergency treatment due to vaginal bleeding and fatigue. Ultrasound revealed a 63 × 27 mm hypoechoic mass extending from the cervical opening to the external opening, with a hemoglobin level of 58.0 g/L on blood routine.

DIAGNOSES

The tissue exhibited a pale-yellow mucinous appearance with distinct tissue boundaries and a fibrous capsule under a microscope. HE staining revealed spindle-shaped fibroblast-like cells with a consistent morphology, thin-walled branching small blood vessels, and dilated blood vessels. Regions with abundant cells and areas with sparse cells were alternately distributed and migrated gradually. Immunohistochemical analysis indicated positive expression of P53, desmin, progesterone receptor, estrogen receptor, epithelial membrane antigen, vimentin, CD68, CD163 in the tumor, but negative expression of P16, S-100, smooth muscle actin, CD117, CD10, STAT-6. CD34 was negative in the tumor cells but positive in the vascular endothelium. The Ki-67 index value was 5%. Pathological examination confirmed a soft tissue angiofibroma of the cervix.

INTERVENTIONS

Emergency hysteroscopic surgery was performed following infusion of 3 units of packed red blood cells. A local excision of the cervical mass was performed.

OUTCOMES

A 1-month follow-up ultrasound showed no abnormal mass in the cervical canal, and there have been no signs of recurrence to date.

LESSONS

Cervical angiofibroma of soft tissue is a rare tumor with a benign clinical manifestation, minimal local recurrence, and no significant metastatic potential. Treatment primarily involves local resection with a focus on achieving negative surgical margins. By presenting this case, we aim to enhance the diagnostic and differential diagnostic capabilities of pathologists in identifying uterine tumors and preventing misdiagnosis.

Clinicopathologic and genetic characterization of angiofibroma of soft tissue: a study of 12 cases including two cases with AHRR::NCOA3 gene fusion

AIMS

Angiofibroma of soft tissue (AFST) is a benign tumour characterised by prominent arborizing blood vessels throughout the lesion. Approximately two-thirds of AFST cases were reported to have AHRR::NCOA2 fusion, and only two cases have been reported to have other gene fusions: GTF2I::NCOA2 or GAB1::ABL1. Although AFST is included in fibroblastic and myofibroblastic tumours in the World Health Organization's 2020 classification, histiocytic markers, especially CD163, have been reported to be positive in almost all examined cases, and it still remains the possibility of a fibrohistiocytic nature of the tumour. Therefore, we aimed to clarify the genetic and pathological spectrum of AFST and identify whether histiocytic marker-positive cells were true neoplastic cells.

METHODS AND RESULTS

We evaluated 12 AFST cases, which included 10 cases with AHRR::NCOA2 and two with AHRR::NCOA3 fusions. Pathologically, nuclear palisading, which has not been reported in AFST, was detected in two cases. Furthermore, one tumour resected by additional wide resection revealed severe infiltrative growth. Immunohistochemical analysis indicated varying levels of desmin-positive cells in nine cases, whereas CD163- and CD68-positive cells were diffusely distributed in all 12 cases. We also performed double immunofluorescence staining and immunofluorescence in situ hybridisation in four resected cases with >10% desmin-positive tumour cells. The results suggested that the CD163-positive cells differed from desmin-positive cells with AHRR::NCOA2 fusion in all four cases.

CONCLUSION

Our findings suggested that AHRR::NCOA3 could be the second most frequent fusion gene, and histiocytic marker-positive cells are not genuine neoplastic cells in AFST.