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

Raf kinase inhibitor protein expression in smooth muscle tumours of the uterus: a diagnostic marker for leiomyosarcoma?

RESEARCH QUESTION

What is the expression pattern of Raf kinase inhibitory protein (RKIP) in different subtypes of leiomyoma (usual type, cellular, apoplectic or haemorrhagic leiomyoma, leiomyoma with bizarre nuclei and lipoleiomyoma) and leiomyosarcoma specimens, and what is its biological role in leiomyosarcoma cells?

DESIGN

Leiomyoma and leiomyosarcoma specimens underwent immunohistochemistry staining. Leiomyosarcoma SK-LMS-1 cell line was RKIP knocked down and RKIP overexpressed, and cell viability, wound healing migration and clonogenicity assays were carried out.

RESULTS

A higher immunohistochemical expression of RKIP was observed in bizarre leiomyomas, than in usual-type leiomyomas. Decreased expression was also found in cellular leiomyoma, with generally absent staining in leiomyosarcomas. Upon RKIP expression manipulation in SK-LMS-1 cell line, no major differences were observed in cell viability and migration capacity over time. RKIP knockout, however, resulted in a significant increase in the cell's ability to form colonies (P = 0.011).

CONCLUSION

RKIP distinct expression pattern among leiomyoma histotype and leiomyosarcoma, and its effect on leiomyosarcoma cells on colony formation, encourages further studies of RKIP in uterine smooth muscle disorders.

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

Uterine smooth muscle tumors of undetermined malignant potential (STUMPs) are an uncommon kind of uterine smooth muscle tumor. It is distinguished by histopathologic and morphologic characteristics that are in between those of a benign leiomyoma and a malignant leiomyosarcoma. From a clinical standpoint, the clinical presentation of STUMP is similar to that of a fibroid. The diagnosis is usually confirmed after surgery. Here, we report the case of a 39-year-old woman who experienced increased menorrhagia, back pain, and pressure sensations during the past six months. She had a well-defined, freely movable lump in her lower abdomen, measuring the size of a 22-cm uterus. The patient exhibited pallor, and her imaging scan showed the presence of an intramural posterior uterine solid mass indistinguishable from fibroid measuring 8.5 × 9 cm. Goserelin acetate (Zoladex 3.6 mg implant) was recommended for a duration of six months. The patient experienced a significant amelioration in menorrhagia and discomfort. However, no reduction in the size of the mass was observed. Myomectomy was made for the suspicion of a malignant transformation. The histology examination confirmed the diagnosis of a STUMP; a hysterectomy was undergone, and the procedure went smoothly. The patient was discharged home in good condition with instructions for long-term follow-up due to a risk of recurrence of about 7%. The lack of standardized and clear clinical and diagnostic criteria for STUMP adds challenges to their management.

Current Concepts in the Imaging of Uterine Sarcomas

Uterine sarcomas are a group of rare uterine tumors comprised of multiple subtypes with different histologic characteristics, prognoses, and imaging appearances. Identification of uterine sarcomas and their differentiation from benign uterine disease on imaging is of critical importance for treatment planning to guide appropriate management and optimize patient outcomes. Herein, we review the spectrum of uterine sarcomas with a focus on the classification of primary sarcoma subtypes and presenting the typical MR imaging appearances.

[Practical diagnostic aspects of uterine leiomyosarcoma in the context of the 2020 WHO classification]

The 2020 WHO Classification defines the spindle cell, epithelioid, and myxoid variants as subtypes of uterine leiomyosarcomas (LMS). Presence of cellular atypia (size variation of polymorphic nuclei > 2-3:1), tumor cell necroses, and mitotic count (usually ≥ 10 MF/10 HPF) are still the key features for diagnostic separation from uterine leiomyomas. Preanalytic variables, staining quality, as well as intralesional geographic distribution may affect the mitotic count. Smooth muscle tumors of uncertain malignant potential (STUMP) still exist as a not yet well-characterized diagnostic entity. Immunohistochemical stains against p16, p53, Ki-67, and WT‑1 may aid differential diagnosis in selected cases. Diagnostic molecular pathology is not yet relevant for diagnosis.

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

Objective Leiomyoma with bizarre nuclei (LBN) is a variant of uterine leiomyoma, which has replaced the previous category of “atypical leiomyoma” and must be distinguished from smooth muscle tumors of uncertain malignant potential (STUMP). However, previously published series of “atypical leiomyoma” might have included both LBN and STUMP, due to the lack of strict diagnostic criteria. Based on such hypothesis, we aimed to define the risk of recurrence in LBN.

Study Design A systematic review and meta-analysis was performed by searching 4 electronic databases for all studies assessing the outcome of patients with “atypical leiomyoma” or LBN. The pooled absolute risk of recurrence was calculated. The included studies were subdivided into two subgroups based on the criteria used: “LBN + STUMP” or “LBN-only”.

Results Twelve studies with 433 patients were included. The pooled risk of recurrence was 5.5% overall. The funnel plot showed two cluster of studies which superimposed to the two subgroups. In the LBN + STUMP cluster/subgroup, the pooled risk of recurrence was 7.7%. In the LBN-only cluster/subgroup, the pooled risk of recurrence was 1.9%. Statistical heterogeneity was null in all analyses.

Conclusion Our results show a risk of recurrence of 1.9% for LBN; higher recurrence rates in older studies are likely due to the inclusion of STUMPs.