• Vol. 39 No. 8, 625–628
  • 15 August 2010

A Clinicopathologic Study of Uterine Smooth Muscle Tumours of Uncertain Malignant Potential (STUMP)



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Introduction: The clinical management of Smooth Muscle Tumours of Uncertain Malignant Potential (STUMPs) remains controversial because little is known about the natural history of these tumours and pathological classifications do not correlate well with clinical outcomes and therefore cannot direct management. The objective of this study was to review a single institution’s experience with STUMP and recommend a rational clinical approach to the management of patients with this histological diagnosis.

Materials and Methods: A systematic review of all diagnoses of STUMP and leiomyosarcoma from the gynaecologic oncology and pathology databases between January 1970 and February 2006.

Results: A total of 18 diagnoses of STUMP and 72 diagnoses of Ieiomyosarcoma were made during the study period. None of these 72 cases of leiomyosarcoma had a prior diagnosis of STUMP. There were no recurrences in the 18 cases of STUMP with all 18 cases being registered as disease-free after 5 years.

Conclusions: We recommend that patients with a diagnosis of STUMP be expectantly managed given the low likelihood of leiomyosarcomatous transformation, the lack of any evidence that adjuvant treatments result in better long-term outcomes and that recurrences are amenable to surgical resection with good outcomes.

Smooth Muscle Tumours of Undetermined Malignant Potential or STUMPs are interesting tumours from both the standpoint of histological diagnosis and classification as well as clinical management mainly because, as a group, its natural history is poorly understood. Prognostic criteria of how STUMP tumours will behave have been studied and proposed based on histological features, surface marker expression and mitotic counts.

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