Solitary Fibrous Tumor of the Adrenal Gland

Abstract

Objectives Solitary fibrous tumor (SFT) is a mesenchymal neoplasm that can arise at various anatomic locations. It is characterized by inv12(q13q13)-derived NAB2::STAT6 fusion, resulting in the nuclear expression of STAT6. Primary SFT of the adrenal gland is rare. We launched a multi-institutional collaboration to comprehend the overarching demographics, clinical and follow-up, macroscopic, microscopic, IHC, and FISH features of 9 patients with SFT of the adrenal gland. Methods We added a series of 9 patients to the collection of adrenal SFTs where the clinicopathologic parameters, including clinical presentation, imaging, histopathology, IHC, molecular profiles, and management and follow-up data, were analyzed comprehensively. A modified 4-variable risk stratification model, including age, tumor size, and necrosis, was applied. Results Our series consisted of 6 male and 3 female patients, ranging in age from 19 to 64 years (mean, 49.3 years). Abdominal pain (4) and fever with abdominal pain (1) were the presenting symptoms in 5 patients. In the remaining 4 patients, the tumors were detected by abdominal imaging for hypertension and diabetes. The size of the tumor ranged from 2 cm to 10.5 cm in maximum dimension. All tumors exhibited the morphology of a spindle cell SFT with a patternless architecture; 3 had a focal storiform arrangement. STAT6 positivity was observed in all tumors, and 7 were positive for CD34. Surgical resection was the primary modality of treatment. No adjuvant therapy was administered. Follow-up ranging from 7 months to 23 months was available for 7 patients. All were alive without disease recurrence or metastasis. Risk stratification placed 8 (88.9%) patients into a low-risk category and 1 into an intermediate-risk category. Conclusions This series is the largest of adrenal SFTs to date. These tumors of the adrenal gland are predominantly spindle cell neoplasms with indolent behavior, with a wide age distribution and a slight male preponderance. Combining our cohort with the previously published cases, the majority of tumors fall into the low-risk category for the propensity to develop metastases. Owing to the rarity and age distribution associated with these tumors, the differential diagnosis is wide and requires a systematic approach for ruling out key differential diagnoses aided by STAT6 IHC.

Adrenal Solitary Fibrous Tumor: A Case Report

“…Notably, in cases documented by Yonly et al [ 6 ] and Kuribayashi et al [ 7 ], symptoms, particularly pain, were reported once the tumor reached approximately 10 cm in size. Another noteworthy consideration is the potential manifestation of paraneoplastic syndromes, such as refractory hypoglycemia due to the insulin-like growth factor release (known as Doege-Potter syndrome) [ 4 , 8 ].…”

“…It is important to note that while STAT6 immunohistochemistry is a sensitive surrogate for detecting STAT6 fusion, it can also exhibit positivity in other entities, such as dedifferentiated liposarcoma, a more commonly occurring tumor in the retroperitoneum. Therefore, the inclusion of MDM2 amplification analysis is imperative in this context to differentiate from dedifferentiated liposarcoma [ 3 , 4 , 11 ].…”

“…Postoperative laboratory and hormonal findings persisted in the reference range. On the basis of previous literature [ 4 ], even though the cases described to date have not recurred, regular follow-up appointments are planned to detect local recurrence or distant metastasis.…”

Giant cell-rich solitary fibrous tumour of the urinary bladder: case report of an unusual histological variant and literature review

“…Solitary fibrous tumour (SFT) is an uncommon mesenchymal neoplasm of fibroblastic origin that usually involves the pleura and was first described by Klemperer and Rabin in 1931 [ 1 ]. Subsequently, it has been found that it can occur in numerous extrathoracic anatomical regions, such as the orbit [ 2 ], salivary glands [ 3 ], respiratory tract [ 4 ], mediastinum [ 5 ], adrenal glands [ 6 ], pelvis [ 7 ], skin [ 8 ], liver [ 9 ], and retroperitoneum [ 10 ]. However, SFTs occurring in the urinary bladder have seldom been reported.…”