Giant cell tumour of bone (GCTB) is a benign, locally aggressive primary bone neoplasm that represents 5% of all bone tumours. The principal treatment approach is surgery. Although generally GCTB is considered only a locally aggressive disease, it can metastasise, and lung metastases occur in 1–9% of patients. To date, only the use of denosumab has been approved as medical treatment for GCTB. Even more rarely, GCTB undergoes sarcomatous transformation into a malignant tumour (4% of all GCTB), but history of this malignant transformation is unclear and unpredictable. Considering the rarity of the event, the data in the literature are few. In this review, we summarise published data of GCTB malignant transformation and we analyse three cases of malignant transformation of GCTB, evaluating histopathology, genetics, and radiological aspects. Despite the rarity of this event, we conclude that a strict follow up is recommended to detect early malignant transformation.

Aims Uterine leiomyosarcoma is a rare and aggressive tumor. The most frequent sites of metastasis are the lung, skin and peritoneum with anecdotal cases of pancreatic and adrenal localizations. In selected cases, surgical excision of metastases is possible, but previous histological confirmation is essential. EUS FNA/B is becoming pivotal for characterization of secondary lesions difficult to approach with standard methods (i.e. videolaparoscopy). Methods We report the case of a 66-years-old woman who was diagnosed with uterine leiomyosarcoma in May 2020 and who underwent bilateral hysteroannessiectomy. A follow-up PET/CT scan performed in August 2022 showed a 34 x 32 mm hypercaptating left adrenal mass and a 20 mm pancreatic body-tail formation. To histologically characterize the lesions, an EUS FNA/B was performed. On ultrasonographic exploration, an inhomogeneous hypoechoic pancreatic mass of 50 x 38 mm in size and a hypoechoic with internal anechoic areas adrenal mass measuring 38 x 36 mm were detected. FNA respectively with 22G and 19G Boston needles were performed on both lesions. Results Histological examination on both masses showed leiomyosarcoma. After multidisciplinary team discussion, the patient started chemotherapy, which is still ongoing. Conclusions Only rare cases of pancreatic and adrenal metastases of leiomyosarcoma are described in literature. Differential diagnosis between primary and secondary lesions is critical. The retroperitoneal localization makes histologic typing challenging; however, in our case both lesions were approachable echo-endoscopically. Echoendoscopy is a minimally invasive method, cost effective, that does not require hospitalization, reducing stress for the patient. Article published online: 14 April 2023 © 2023. European Society of Gastrointestinal Endoscopy. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany