Histologically benign metastasizing tenosynovial giant cell tumor mimicking metastatic malignancy: A case report and review of literature

Abstract

Diffuse-type tenosynovial giant cell tumor (D-TGCT), otherwise known as pigmented villonodular synovitis, is a locally aggressive tumor which can show multiple recurrences but is rarely associated with metastasis. A handful of studies have elucidated the imaging features and clinical course in metastatic D-TGCT with malignant transformation on histology. However, only 5 cases of metastatic D-TGCT with benign histological features have been reported in the literature, with the clinical course and prognosis reported in only 1 case. Therefore, relatively little is known about the implications of histologically benign metastasis on the role of imaging, management, and clinical outcomes. We report a case of a 51-year-old female with recurrent D-TGCT localized to the knee that metastasized to the lymph nodes and soft tissue 3 years after above-the-knee amputation and 16 years after initial diagnosis of localized D-TGCT, despite benign histologic features on lymph node excision. This case highlights the necessity of timely MRI imaging to prevent delayed diagnosis, the role of histological findings on treatment response, and clinical outcomes associated with metastasized D-TGCT.

Management of a Huge Tenosynovial Giant Cell Tumor of the Wrist

“…Localized TGCT generally occurs in the form of well-delineated lesions that do not penetrate the tendons. However, the diffuse type which is generally aggressive occurs with homogeneous soft tissue masses, and is associated with joint destruction and invasion [14]. The TGCT in our case also aggressively invaded the wrist joint capsule and adjacent flexor tendon.…”

Keratin-Positive Giant Cell Tumor of Bone and Soft Tissue With HMGA2::NCOR2 Fusion in Children Under 10 With Response to Imatinib Therapy: A Case Series

“…Surgery has been the standard treatment for extra-articular and locally aggressive diffuse-type TGCT (dTGCT), but the recurrence rate is high. 15 Rare cases of histologically benign dTGCT with metastatic disease have been described, 16 and a subset of dTGCT show overtly malignant features and aggresivity. 17 Targeted therapy using CSF1/CSF1R inhibitors has shown clinical success for these unresectable or metastasizing tumors.…”

The Scream: Benign Thyroid Tissue as a Lateral Neck Mass

“…In fact, histologic appearance may not predict tumor behavior at all. Some morphologically benign-appearing lesions are proven to be malignant through demonstration of metastases 20,21 . In contrary, some metastases may not exhibit all the cytomorphological characteristics necessary to identify a primary tumor as malignant.…”

“…Some morphologically benign-appearing lesions are proven to be malignant through demonstration of metastases. 20,21 In contrary, some metastases may not exhibit all the cytomorphological characteristics necessary to identify a primary tumor as malignant. In this case, the lateral neck mass was strongly suspected to be a metastasis at least in part because definitive radiological examination had not occurred prior to biopsy.…”