Stanford parameters stratify the risk of recurrence in gynecologic smooth muscle tumors of uncertain malignant potential

Abstract

Smooth muscle tumor of uncertain malignant potential (STUMP) is an ill‐defined category of neoplasms, which represent a diagnostic challenge. We aimed to assess whether the Stanford parameters, that is, high mitotic index (≥10/10HPF), significant atypia (moderate‐to‐severe), and coagulative tumor cell necrosis (CTCN), even when focal or ambiguous, may be used to stratify the risk of recurrence in gynecological smooth muscle tumor of uncertain malignant potential (STUMP). Electronic databases were searched from their inception to October 2019. All studies assessing the Stanford parameters in gynecological STUMP series were included. STUMPs were subdivided according to the presence of the three Stanford parameters: high mitotic index, significant atypia, and CTCN. A Kaplan–Meier survival analysis was performed for recurrence‐free survival; hazard ratio (HR) was calculated in each category. Fourteen studies with 219 STUMPs were included. In 15.5% of cases, none of the three Stanford parameters were present, with a recurrence risk of 5.9%; 2.7% of cases showed high mitotic index alone, with a recurrence risk of 0% (HR = not calculable); 43.8% of cases showed significant atypia alone, with a recurrence risk of 18.7% (HR = 3.3; p = 0.012); 26.5% of cases showed CTCN alone, with a recurrence risk of 17.2% (HR = 3.1; p = 0.029); and 11.4% of cases showed at least two Stanford parameters, with a recurrence risk of 32% (HR = 7.5; p = 0.003). Stanford parameters may stratify the risk of recurrence of STUMP. Significant atypia and CTCN, but not high mitotic index, may be stand‐alone risk factors for recurrence in STUMP. The presence of at least two Stanford parameters, even if equivocal (e.g., uncertain or focal CTCN, focal significant atypia, mitotic index around 10/10HPF), might still be enough to support a diagnosis of leiomyosarcoma. Further studies are necessary in this field.

A Case Report of a Uterine Smooth Muscle Tumor of Undetermined Malignant Potential (STUMP): A Diagnostic Dilemma and Management Challenges

“…Neither the preoperative investigations nor intraoperative findings gave a hint of the diagnosis. Only a histopathology report confirmed the case, consistent with earlier reports [4,5]. This case was unique because it failed to respond to the Zoladex implant despite the patient's adherence to therapy, which underscores a more aggressive neoplastic process.…”

Protracted clinical course of an AFF1 fusion positive uterine smooth muscle tumor causing diagnostic confusion over a course of 15 years

“…The risk of recurrence of STUMPs was described in a review of 14 studies that included 219 patients, at 17.4% ( Travaglino et al, 2021 ). STUMPs defined by high mitotic index alone was not associated with recurrences, suggesting that high mitotic activity alone should not warrant a diagnosis of STUMP, and in cases of either significant atypia or coagulative tumor cell necrosis the risk of recurrence approached 20% ( Travaglino et al, 2021 ).…”

“…The risk of recurrence of STUMPs was described in a review of 14 studies that included 219 patients, at 17.4% ( Travaglino et al, 2021 ). STUMPs defined by high mitotic index alone was not associated with recurrences, suggesting that high mitotic activity alone should not warrant a diagnosis of STUMP, and in cases of either significant atypia or coagulative tumor cell necrosis the risk of recurrence approached 20% ( Travaglino et al, 2021 ). Additional risk factors for recurrence have included abnormal p16 and p53 expression, genomic index, atypical mitotic figures, vascular involvement, irregular margins, subserosal tumor location, and myomectomy ( Shim et al, 2020 ).…”

“…Benign leiomyomas lack these features, while tumors with some features are referred to as smooth muscle tumors of uncertain malignant potential (STUMP). The recurrence risk of STUMPs are estimated to be 7–20% ( Travaglino et al, 2021 ), and some have recurred as LMS. We describe a patient with an unusual clinical course whereby over the span of 15 years from hysterectomy for leiomyomas, she had multiple recurrences of the same smooth muscle tumor, which subsequently recurred showing frankly malignant LMS.…”

Risk of Recurrence in Uterine Leiomyoma with Bizarre Nuclei: a Systematic Review and Meta-Analysis

“…Our findings also support that the higher recurrence rates observed in older studies are due to the inclusion of STUMP. In fact, smooth muscle tumors with significant atypia in the absence of increased mitotic index or CTCN represent the majority of cases labeled as STUMP in the literature; these STUMPs shave shown a considerable risk of recurrence (about 20%) 37 . The recurrence rate of 7.7% observed in the series of so-called “atypical leiomyoma” appears therefore consistent with an admixture of LBN and STUMP.…”