When Fibroids Fool: A Case Report of Ruptured Uterine Leiomyoma Mimicking Ovarian Malignancy

INTRODUCTION

Uterine fibroids, or leiomyomas, are the most common benign tumors of the female reproductive system, often detected during routine clinical examinations or imaging studies.^[1] These tumors are generally asymptomatic but can cause significant symptoms such as pelvic pressure, heavy menstrual bleeding, and infertility, depending on their size, location, and number.^[2] While fibroids are typically easy to diagnose based on their characteristic clinical and radiological features, rare cases can present with atypical manifestations, leading to diagnostic challenges. One such rare presentation is a ruptured fibroid, which can mimic ovarian malignancy due to overlapping clinical features such as abdominal pain, bloating, nausea, vomiting, ascites, and the presence of adnexal masses.^[3] Accurate differentiation between these conditions is crucial, as the management strategies differ significantly. Misdiagnosis often results in unnecessary aggressive surgical interventions. This case report discusses a 42-year-old woman with a ruptured fibroid that initially raised suspicion of ovarian malignancy, emphasizing the diagnostic challenges and the importance of accurate preoperative evaluation in such rare cases.

CASE REPORT

A 42-year-old multiparous female presented to the emergency department at Sri Ramachandra Medical College, Chennai (SRMC) with acute abdominal pain, nausea, vomiting, loose stools, and giddiness over the past four days. She had been previously diagnosed with anemia at an outside the hospital and had received blood transfusion therapy. The patient also reported intermittent abdominal discomfort, shortness of breath, and menstrual irregularities but had no history of urinary discomfort, constipation, or family history of malignancy or weight loss.

Upon physical examination, the patient had a distended abdomen with tenderness in the right iliac fossa and suprapubic region. A large, firm mass measuring approximately 12 x 10 cm was palpable in the right lower quadrant, extending across to the left side. The lower margin of the mass could not be delineated. A speculum examination revealed cervical erosion on the anterior lip with several Nabothian cysts. On per vaginal examination, a bulky uterus and fullness in the right forniceal area were noted.

Imaging studies were performed to further investigate the mass. A contrast-enhanced computed tomography (CECT) scan done at an outside facility revealed a large multiloculated necrotic mass measuring 10.2 ´ 12.2 ´ 7.5 cm in the right adnexa, extending into the pelvis and pouch of Douglas (POD), along with moderate ascites. The uterus was found to be bulky with multiple fibroids, both intramural and subserosal. The endometrial thickness was 19 mm, with polypoid components observed in the cavity. These findings raised suspicion of ovarian malignancy, prompting referral to our center for further evaluation.

An ultrasound performed at our center confirmed these findings, showing a bulky retroverted uterus with multiple fibroids. A large heterogeneous mass measuring 9.3 ´ 6.9 ´ 5.8 cm was observed in the right adnexa with solid cystic components in close proximity to the uterus. The right ovary could not be separately visualized, and moderate free fluid was noted in the POD. The left ovary and adnexa appeared normal.

Laboratory tests revealed elevated tumour markers, with an lactate dehydrogenase (LDH) level of 606 U/L and CA-125 level of 215 U/mL. These findings, along with the imaging results, suggested a high likelihood of ovarian malignancy. A Risk Malignancy Ratio of 645 was calculated, further raising concerns.

Ultrasound sonography (USG)-guided aspiration was performed preoperatively to aspirate the free ascitic fluid from the abdomen, and the fluid was sent for cytological analysis. Consequently, a diagnostic laparoscopy was planned but converted to staging laparotomy due to intraoperative findings. Approximately 500 mL of hemoperitoneum was noted [Figure 1]. On exploration, a ruptured fibroid measuring 9 x 7 cm was found on the fundus of the uterus with a small venous bleeder located at the posterior aspect of the fibroid, where engorged vessels were visible [Figures 2 and 3]. Multiple subserosal and intramural fibroids were also noted. The bilateral fallopian tubes and ovaries appeared normal [Figure 4], as did the other abdominal organs, including the appendix and liver. Given the high suspicion of malignancy and a premenopausal woman, a total abdominal hysterectomy (TAH) with bilateral salpingo-oophorectomy (BSO) was performed. In addition, a bilateral pelvic lymphadenectomy was carried out, and specimen of the uterus, fallopian tubes, ovaries, and lymph nodes were sent for histopathological examination.

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Figure 1:

Hemoperitoneum on laparoscopy

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Figure 2:

(a) Fibroid found to be arising from the posterior fundal aspect of the uterus, (b) Many engorged vessels.

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Figure 3:

Gross examination of fibroid.

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Figure 4:

Tubes and Ovaries intact - (a) Right side, (b) Left side.

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Histopathological examination of the specimen confirmed it to be a benign leiomyoma, showing interlacing smooth muscle fibers with focal areas of infarction and congestion. There was no evidence of atypia or increased mitosis. Cytological analysis of the ascitic fluid taken preoperatively, was negative for malignant cells and showed reactive mesothelial cells and lymphocytes in a hemorrhagic background.

Postoperatively, the patient had a smooth recovery and was discharged with no complications. Follow-up visits showed no recurrence of symptoms. This case highlights the rare presentation of a ruptured uterine fibroid that mimicked ovarian malignancy and emphasizes the importance of thorough diagnostic evaluation and considering fibroids in the differential diagnosis of adnexal masses.

DISCUSSION

Uterine fibroids (leiomyomas) are the most common benign tumors of the female reproductive system and typically present with symptoms such as heavy menstrual bleeding, pelvic pressure, and infertility.^[1] In rare cases, complications like fibroid rupture can occur, which may lead to clinical features that resemble ovarian malignancy, such as abdominal pain, bloating, nausea, vomiting, ascites, and adnexal masses. This overlap in symptoms can pose a diagnostic challenge, as seen in the present case.

Leiomyomas are classified based on their location into three categories: submucosal (projecting into the endometrial canal), intramural (within the substance of the myometrium), and subserosal (located beneath the serosal layer of the uterus).^[4] Subserosal fibroids, which are located on the outer layer of the uterus, can sometimes grow large and distort surrounding structures, making them more likely to present with atypical symptoms, as observed in our case. When such fibroids undergo degeneration or rupture, they can cause significant complications, including ascites and the formation of masses that may mimic malignancy on imaging. Pedunculated fibroids, which are attached to the uterus by a stalk, may also have obscure origins and could be mistaken for ovarian lesions, adding to the diagnostic confusion.^[5] Yorita et al in a review article, noted that, among 17 cases mimicking ovarian tumors, most (70%) were actually subserosal pedunculated masses and six cases had multilocular cystic morphology.^[6]

The primary diagnostic pitfall in this case was the failure to visualize the pedicle of the subserosal fibroid, likely due to distortion caused by its large size and rupture. The presence of an adnexal mass, ascites, and elevated CA-125 and LDH levels are often indicative of ovarian cancer, but these can also be seen in benign conditions like fibroids, especially when complicated by rupture and infarction.^[7] The inability to visualize the right ovary separately on imaging further complicated the diagnosis.

Misdiagnosis often leads to unnecessary surgical interventions, as seen in this case, where the initial suspicion of malignancy led to extensive surgery, including a TAH with BSO with Bilateral Pelvic Lymphadenectomy. Despite the aggressive surgical approach, the histopathological analysis confirmed a benign condition, reinforcing the need for comprehensive preoperative evaluation.^[8]

This case underscores the importance of considering ruptured fibroids in the differential diagnosis of adnexal masses. Thorough clinical and imaging evaluation, combined with cautious preoperative planning, can help prevent overtreatment and unnecessary morbidity.

CONCLUSION

This case underscores the importance of including a ruptured uterine fibroid in the differential diagnosis of adnexal masses, especially in premenopausal women. Diagnostic challenges arise due to overlapping symptoms and imaging findings that can mislead clinicians. Although the initial suspicion of malignancy led to extensive surgery, histopathological examination confirmed a benign fibroid, emphasizing the necessity for caution in interpreting imaging results and tumour markers in cases with atypical presentations. Clinical suspicion and comprehensive imaging evaluation are key to distinguishing benign conditions like fibroids from malignancies; thus, thorough clinical and imaging evaluation, combined with cautious preoperative planning, can help prevent overtreatment and unnecessary morbidity.