Physicians at the Clinic for Obstetrics and Women’s Health at the University Medical Center of the Johannes Gutenberg University Mainz in Germany have reported a rare presentation of extrauterine pararectal leiomyosarcoma diagnosed one year after a total laparoscopic hysterectomy performed without morcellation. The patient had initially undergone complete surgical removal of the uterus and adnexa for presumed benign uterine leiomyomas, with subsequent histopathology confirming non-malignant tissue. The delayed discovery of an aggressive pelvic smooth muscle malignancy in the absence of uterine tissue fragmentation represents an exceptional clinical scenario that underscores ongoing diagnostic difficulties in distinguishing benign fibroids from soft tissue sarcomas.

Uterine leiomyomas represent the most prevalent benign tumors of the female genital tract, occurring in up to fifty percent of women of reproductive age. While hysterectomy permanently eliminates the risk of intrauterine fibroid recurrence, extrauterine parasitic leiomyomas can occasionally emerge following surgical interventions, particularly procedures involving tissue morcellation techniques. In contrast, leiomyosarcomas are malignant smooth muscle tumors with an estimated annual incidence of 0.4 cases per 100,000 women, peaking between ages 45 and 59. Delayed sarcoma diagnoses following total hysterectomy performed entirely without morcellation remain exceedingly uncommon in published medical literature.

The patient was a 47-year-old woman, gravida II, para I, who initially sought gynecological evaluation due to progressively enlarging uterine fibroids accompanied by left-sided pain during defecation. Her complex clinical history included childhood acute lymphoblastic leukemia diagnosed in early childhood and relapsing two years later, which had been treated with anthracycline-containing chemotherapy and bone marrow transplantation. In early adulthood, she developed thyroid carcinoma that required thyroidectomy and radioiodine therapy. Additional co-morbidities included type II diabetes mellitus, arterial hypertension, and osteopenia, alongside a documented BRCA1 mosaic detected during previous genetic counseling for familial gynecological tumors.

Initial pelvic evaluation via transvaginal ultrasound identified multiple uterine fibroids, including a suspected pedunculated anterior wall mass measuring 3.7 by 2.3 centimeters. Given her medical background and clinical symptoms, surgeons performed a total laparoscopic hysterectomy with bilateral adnexectomy. The uterus was removed intact through the vagina via colpotomy without the use of morcellation. Intraoperative inspection confirmed an enlarged fibroid uterus, normal fallopian tubes, and bilateral ovarian adenofibromas, without evidence of extrauterine lesions. Formal histopathology confirmed multiple intramural fibroids, the largest measuring 5.0 centimeters, composed of plump-spindle cells arranged in interwoven fascicles with no mitotic elevation or features of malignancy.

Postoperative surveillance one year later revealed a new pelvic abnormality during routine transvaginal ultrasound, demonstrating a 4-centimeter heterogeneous hyperechogenic lesion adjacent to the pelvic wall. Subsequent magnetic resonance imaging revealed a well-circumscribed, T2-heterogeneous mass measuring 5.6 by 5.5 by 4.3 centimeters situated in the left pararectal region. The pararectal lesion showed bizarre contrast enhancement but retained a clear tissue demarcation from the rectum. Imaging also detected a separate, smoothly bordered 11 by 7 by 9 millimeter contrast-enhancing nodule located anteriorly between the levator ani and obturator internus muscles at the level of the urethra and vagina.

A secondary laparoscopic intervention was undertaken to address the suspected parasitic fibroid recurrence. Upon pelvic entry, surgeons observed rightward displacement of the rectum caused by a 7 by 7 centimeter partially degenerative and necrotic mass in the left pararectal space. The lesion was separated from surrounding anatomical structures, enucleated in its entirety, and extracted intact inside an endoscopic retrieval bag. Further exploration into the Retzius space and the deep levator layer on the right side demonstrated normal anatomy without a visible mass, while intraoperative ultrasound positioned the paraurethral lesion deep beneath the endopelvic fascia, leading the team to abandon periurethral dissection.

Microscopic evaluation of the paraffin-embedded pararectal tissue contradicted the primary benign diagnosis, revealing a partially necrotic mesenchymal tumor composed of pleomorphic spindle cells with bizarre nuclei and up to 8 mitoses per 10 high-power fields. Immunohistochemical assays showed strong positivity for actin and caldesmon, partial reactivity for desmin, and negativity for pancytokeratin and S100, alongside a Ki-67 proliferation index of 30 percent and an absence of MDM2 gene amplification by fluorescence in situ hybridization. These parameters established an FNCLCC grade 2 leiomyosarcoma with a total score of 5, indicating microscopic margin involvement despite complete macroscopic surgical clearance.

Systemic oncological staging was conducted using whole-body 18-F-fluorodeoxyglucose positron emission tomography combined with computed tomography following administration of 150 megabecquerels of tracer. The scan excluded distant thoracoabdominal metastases and pathological lymphadenopathy, identifying only mild residual uptake in the left pararectal surgical bed consistent with postoperative healing, while the stable paraurethral nodule demonstrated no tracer avidity. The tumor was staged as T2bN0M0, corresponding to FIGO stage IIB. Although an initial board consensus recommended adjuvant chemotherapy with doxorubicin and dacarbazine, internal medicine specialists advised against anthracyclines due to high cumulative childhood exposure and secondary cardiotoxicity risks, shifting management to structured surveillance.

The findings provide an important contrast to larger historical cohorts evaluating delayed sarcoma emergence after gynecological surgery. In an investigation of 941 patients undergoing hysterectomy with power morcellation by Tan-Kim and colleagues, 0.3 percent received a delayed sarcoma diagnosis after an initial benign finding, with a median interval of 6 years. Conversely, among 2,582 patients undergoing hysterectomy without morcellation in that same study, primary pathology identified sarcoma at the time of initial surgery in 0.19 percent of cases, with zero instances of delayed sarcoma detection, underscoring the singular nature of this pararectal presentation.

Several pathophysiological mechanisms have been proposed to explain the clinical presentation, including the malignant transformation of an unrecognized pre-existing pararectal parasitic fibroid, de novo pelvic retroperitoneal sarcomagenesis, or late mutagenic sequelae of childhood anthracycline therapy. While a direct causal role between BRCA1 alterations and smooth muscle tumors remains unproven, homologous recombination repair deficiencies are recognized in uterine sarcoma biology. The authors noted that initial uterine histology was not formally re-reviewed due to unequivocally benign features at primary surgery, concluding that solitary pelvic masses appearing after intact hysterectomies require thorough histopathological examination.

The diagnostic difficulty surrounding pelvic smooth muscle neoplasms stems from the inability of physical examination and routine imaging modalities, including ultrasound and computed tomography, to definitively differentiate between benign leiomyomas and malignant soft tissue sarcomas. Magnetic resonance imaging represents the primary modality of choice for distinguishing benign fibroids from lesions displaying abnormal tissue metabolism, though definitive differentiation ultimately requires histopathological analysis. Characteristic imaging findings highlighted broad contact and mild mechanical impression on the mid-rectal segment on coronal T2-weighted sequences, accompanied by hypointense regions on axial post-contrast T1-weighted fast spin echo sequences with fat suppression. At the molecular level, uterine leiomyosarcomas frequently harbor alterations in the tumor suppressor genes p53 and Rb-1, while approximately ten percent of cases display mutations in BRCA2. Furthermore, extrauterine leiomyosarcomas typically arise in the retroperitoneum or the extremities, rendering a localized pararectal manifestation following complete uterine extirpation an exceptional rarity. Because prior exposure to antineoplastic chemotherapy or ionizing radiation heightens the susceptibility to developing secondary soft tissue sarcomas, clinicians must systematically account for underlying genetic predispositions whenever secondary malignancies emerge following cancer therapies.

Published surgical literature contains few documented parallels to delayed extrauterine sarcoma manifestations occurring after total hysterectomy. One closely related report by Burde and colleagues described the development of a pelvic leiomyosarcoma in a 50-year-old patient approximately three years after undergoing transabdominal hysterectomy with bilateral adnexectomy. In that instance, the primary surgical specimen was initially categorized as a benign leiomyoma, but subsequent reevaluation of the original tumor tissue revised the histological diagnosis to a smooth muscle tumor of uncertain malignant potential, designated as STUMP. Another distinct case report documented a pelvic leiomyosarcoma presenting four years following laparoscopic-assisted supracervical hysterectomy performed in conjunction with morcellation. However, in that surgical scenario, the newly discovered sarcoma was found intraoperatively adherent to the residual cervical stump, suggesting that the neoplastic growth originated directly from the retained cervical tissue rather than representing an isolated pelvic implantation.

These comparative cases accentuate an ongoing dilemma regarding how to distinguish occult uterine sarcomas prior to performing organ-preserving surgeries or morcellation procedures. Minimally invasive laparoscopic myomectomy delivers safety and fertility preservation comparable to open laparotomy while reducing perioperative morbidity; nevertheless, inadvertent surgical intervention on an occult sarcoma creates a substantial risk of intraoperative malignant cell dissemination that significantly worsens clinical prognosis. While investigators have hypothesized that mechanical morcellation can disperse myoma cells that subsequently undergo malignant transformation, or scatter occult malignant cells overlooked during initial fragmented tissue assessment, such dispersal models fail to explain tumors arising after intact uterine extraction. Because the patient’s primary uterus was removed intact without morcellation, alternative etiologies such as an overlooked pre-existing parasitic implant or an independent retroperitoneal neoplasm must be considered.

Management of the secondary lesion further underscored the importance of tailored surveillance strategies. Intraoperative transvaginal ultrasound confirmed that the contrast-enhancing paraurethral lesion was positioned deep beneath the endopelvic fascia below the levator ani musculature, prompting surgeons to halt further abdominal periurethral dissection to avoid unnecessary tissue disruption. Structured follow-up pelvic magnetic resonance imaging performed three months postoperatively verified that this paraurethral nodule remained size-stable, justifying ongoing conservative imaging surveillance without invasive biopsy. Because gynecological oncology currently lacks established consensus guidelines for monitoring pelvic fibroids in reproductive-aged women following surgical intervention, this presentation highlights the vital necessity of meticulous histopathological review when post-hysterectomy pelvic masses arise. In patients presenting with prior cancer treatment histories and genetic alterations such as BRCA1 mosaic variants, vigilant individualized clinical surveillance beyond conventional organ-specific screening remains crucial.

Subject of Research: Extrauterine leiomyosarcoma recurrence following total laparoscopic hysterectomy without tissue morcellation

Article Title: Pararectal Leiomyosarcoma Following Total Laparoscopic Hysterectomy (TLH) for Initially Diagnosed Uterine Leiomyoma

Article References: Monjé, N., Alexa, M., Hasenburg, A., & Degirmenci, Y. (2026). Pararectal Leiomyosarcoma Following Total Laparoscopic Hysterectomy ( TLH ) for Initially Diagnosed Uterine Leiomyoma. Clinical Case Reports, 14(11), Article e73090. https://doi.org/10.1002/ccr3.73090

Image Credits: AI Generated

DOI: 10.1002/ccr3.73090

Keywords: leiomyosarcoma, uterine fibroids, laparoscopic hysterectomy, gynecologic oncology, pararectal mass, BRCA1 mosaic, sarcoma diagnosis, soft tissue sarcoma, Pararectal, Following, Total, Laparoscopic