Ruptured Subserosal Pyomyoma Presenting as Peritonitis in the Early Postpartum Period: A Case Report

Abstract

Introduction

Uterine leiomyomas (fibroids) are common benign tumors in women of reproductive age. Pyomyoma (suppurative leiomyoma) is a rare life-threatening complication arising from infarction and secondary infection of a fibroid, most often occurring during pregnancy or the postpartum period. Diagnosis is challenging due to nonspecific presentations.

Case Presentation

We report a 24-year-old primiparous woman (G1P1) who presented on postpartum day 9 with acute abdominal pain, fever, and leukocytosis. Imaging (CT) revealed a large subserosal fibroid with intraperitoneal free fluid and pockets of gas.

Management and Outcome

The patient underwent emergent exploratory laparotomy. A 10×15 cm perforated, purulent pedunculated subserosal leiomyoma with surrounding adhesions was identified, and postpartum abdominal hysterectomy was performed for source control. Postoperative broad-spectrum antibiotics were administered. The patient improved rapidly, with normalization of white blood cell count and resolution of symptoms, and was discharged home in good condition.

Conclusion

This case highlights the need for high suspicion for pyomyoma in postpartum patients with fibroids who develop severe abdominal pain and sepsis. Prompt imaging and surgical intervention are critical to avoid morbidity and mortality from this rare complication.

Introduction

Uterine leiomyomas (fibroids) are common benign smooth muscle tumors of the uterus.^1,2 By age 50 years, as many as 70–80% of women have fibroids, with peak prevalence in the 30–50-year age group.^1,3 Risk factors for fibroids include African ancestry, increasing age, positive family history, obesity, and early menarche. ⁴ Only a minority of fibroids cause symptoms; the remainder are often asymptomatic. ³ Fibroids may undergo various degenerative changes, especially during pregnancy and the postpartum involution period. ⁵

A rare but severe complication is pyomyoma, a suppurative infection of a uterine leiomyoma.^6,7 Pyomyoma results from infarction or ischemic necrosis of fibroid tissue followed by bacterial colonization.^6,7 It most commonly occurs in the setting of pregnancy, the postpartum period, post-abortion, or menopause, often precipitated by uterine instrumentation or vascular insufficiency.^6,8 Known predisposing factors include recent pregnancy or abortion, cesarean delivery, gynecologic procedures such as curettage or uterine artery embolization, diabetes, and immunocompromise.^6,9 Because pyomyoma is exceedingly rare (fewer than 100 cases reported in the literature), ¹⁰ its true incidence is unknown.

Clinically, pyomyoma often presents with nonspecific systemic and abdominal symptoms: fever, lower abdominal or pelvic pain, leukocytosis, and occasionally a palpable pelvic mass. ¹¹ In the absence of an obvious infection source, the triad of fibroid, sepsis, and no alternate focus should raise suspicion for pyomyoma. ⁸ However, the presentation can mimic more common postpartum conditions, such as endometritis, retained products of conception, tubo-ovarian abscess, or septic pelvic thrombophlebitis.^8,12 This often leads to delays in diagnosis. Imaging with ultrasound may show a heterogeneous uterine mass, but computed tomography (CT) or magnetic resonance imaging (MRI) is frequently needed to better characterize a fluid- or gas-containing necrotic fibroid.^13,14 Even with imaging, definitive diagnosis is frequently made intraoperatively or on histopathology. ¹⁴

We present a rare case of a postpartum primigravida with a perforated subserosal leiomyoma causing peritonitis. The patient required an emergent postpartum abdominal hysterectomy for infection source control. This report reviews the pathogenesis, diagnostic challenges, and management considerations of pyomyoma in pregnancy and the puerperium.

Case Presentation

A 24-year-old primiparous woman (G1P1) presented to the emergency department on postpartum day 9 with a 9-day history of progressively worsening abdominal pain, initially localized to the epigastric region but later generalized. The pain was accompanied by multiple episodes of vomiting and transient watery diarrhea. She had delivered vaginally without complications and had no known chronic illnesses.

During antenatal care, obstetric ultrasound identified a pedunculated subserosal leiomyoma arising from the uterine fundus, consistent with a FIGO type 7 fibroid, which remained stable on serial follow-up scans and was not associated with fetal growth restriction or other major obstetric complications. The pregnancy progressed to term, and she had a spontaneous vaginal delivery of a healthy neonate without immediate complications. She remained well initially after delivery, but progressively worsening abdominal pain began shortly thereafter and continued until postpartum day 9, when she presented to the emergency department. At presentation, she was a 24-year-old primiparous woman (G1P1) with a 9-day history of abdominal pain, initially localized to the epigastric region but later generalized. The pain was accompanied by multiple episodes of vomiting and transient watery diarrhea. She had no known chronic illnesses.

On examination, the patient appeared acutely ill. Her vital signs were notable for tachycardia (pulse: 140 bpm). Abdominal examination revealed diffuse tenderness with signs of peritonitis and fluid collection.

Laboratory investigations showed marked leukocytosis (WBC: 20.3×10^3/μL, 88% neutrophils), anemia (Hb: 8.0 g/dL), and elevated platelet count (526×10^3/μL).

Abdominal ultrasound showed free air under the right hemidiaphragm and moderate ascites. Contrast-enhanced computed tomography (CT) revealed a 15×8 cm mottled lesion superior to the uterine fundus with intraperitoneal fluid and internal air foci, consistent with an infected or perforated pedunculated subserosal fibroid. The uterus was enlarged.

The patient underwent emergent exploratory laparotomy, which revealed a 10×15 cm perforated, purulent subserosal leiomyoma with inflammatory adhesions to the bowel and fallopian tubes (Figures 1 and 2). Due to the extent of infection and tissue necrosis, a postpartum abdominal hysterectomy was performed (Figure 3). The peritoneal cavity was thoroughly irrigated, and the surgical field was closed in layers. Histopathology confirmed an infected leiomyoma with degenerative changes and acute suppurative inflammation, consistent with pyomyoma.

Figure 1.

(A-B) Intraoperative photograph showing a large, pus-filled subserosal uterine leiomyoma with surrounding inflamed adhesions

Figure 2.

Intraoperative view demonstrating a perforated and purulent subserosal uterine fibroid

Figure 3.

The resected uterus with attached degenerated pedunculated leiomyoma, showing signs of perforation and suppuration

Postoperative recovery was uneventful. The patient began oral intake and ambulation on postoperative day 1. On day 2, she developed mild abdominal distension and incisional tenderness. Pelvic ultrasound identified a 6×5 cm fluid collection, which later increased to 10×5 cm by day 4. Aspiration yielded sterile, straw-colored fluid. She was managed conservatively with serial imaging, wound care, broad-spectrum antibiotics (ceftriaxone and metronidazole), and supportive therapy including iron supplementation.

Her hematologic parameters improved steadily (Table 1), with WBC decreasing from 20.3×10^3/μL at admission to 8.2×10^3/μL by postoperative day 10. Hemoglobin and platelet levels also stabilized. The patient was discharged in good condition and referred for follow-up care.

Table 1.

Hematologic Trends During Hospitalization

Time	WBC (10^3/μL)	Hemoglobin (g/dL)	Platelets (10^3/μL)
Admission (pre-op)	20.3	8.0	526
Post-op Day 2	14.0	12.3	542
Post-op Day 3	14.8	13.6	578
Post-op Day 10	8.2	11.2	620

Discussion

This case underscores the importance of considering pyomyoma in the differential diagnosis of acute abdomen in the postpartum period. While common causes of postpartum fever and abdominal pain include endometritis, uterine atony with hemorrhage, and retained products, rare causes such as leiomyoma complications must also be recognized.^6,12 In our patient, the combination of severe abdominal pain, marked leukocytosis, and CT findings (free intra-abdominal air and fluid adjacent to a known uterine fibroid) raised concern for an intra-abdominal catastrophe. Prompt surgical exploration confirmed a perforated, pus-filled fibroid, which is atypical but critical to diagnose early.

Postpartum physiological changes may predispose fibroids to infarction. After delivery, the uterus rapidly involutes and uterine blood flow decreases substantially, which may compromise the perfusion of large or pedunculated myomas.^6,8 In addition, fibroids may undergo torsion if attached to the uterine wall by a long stalk. ¹⁵ These factors can lead to ischemic necrosis. Superimposed bacterial infection, which is commonly polymicrobial, can convert a “red-degenerated” fibroid into an abscess-filled pyomyoma. ⁸ The infection typically involves a combination of aerobic and anaerobic organisms. Frequently isolated pathogens include Staphylococcus aureus, Streptococcus haemolyticus, Proteus species, Streptococcus agalactiae, Escherichia coli and Enterococcus faecalis. Anaerobic bacteria such as Prevotella, Peptostreptococcus, and other gram-negative rods are also commonly implicated.^8,11 In our patient, secondary infection with anaerobic organisms was suggested by foul-smelling pus intraoperatively.

Myomectomy was not attempted because the fibroid was perforated, purulent, and densely adherent to surrounding structures, with extensive infection and tissue necrosis, making uterine-sparing surgery unsafe and unlikely to achieve adequate source control.^11,12 Although fertility preservation is desirable in young primiparous patients, hysterectomy was required in this case because of perforation, diffuse peritonitis, extensive necrosis, and severe adhesions.^3,4,11 In this setting, uterine-sparing surgery would likely have been insufficient for source control and could have placed the patient at risk of ongoing sepsis. ¹³

Diagnosing pyomyoma is notoriously challenging. Symptoms overlap with other postpartum infections.^8,12 Imaging can help: on CT or MRI, a pyomyoma often appears as an enlarged fibroid with central nonenhancement (necrosis) and possible gas formation.^13,14 In our patient, CT revealed heterogenous mass and intraperitoneal air, suggesting a perforation. However, these findings are not specific, and pyomyoma is often misdiagnosed until laparotomy. ¹⁴ The literature emphasizes maintaining a high index of suspicion when a patient with known fibroids presents with sepsis of unknown origin.^8,13

Differential diagnoses included uterine rupture, septic pelvic thrombophlebitis, or visceral perforation. However, imaging localized the abnormality to the uterus. Intraoperative findings confirmed that the uterine fibroid itself was the source. Clinicians should also consider pyomyoma when encountering a pelvic mass with adjacent signs of infection on imaging. A previously reported postpartum case presented with similar findings of sepsis due to pyomyoma, highlighting the importance of early recognition and intervention. ¹³

Management of pyomyoma requires a combination of broad-spectrum antibiotics and surgical intervention. In stable patients without peritonitis, a trial of antibiotics with uterine-conserving surgery (myomectomy) has been successfully performed, especially in young patients desiring fertility, provided the infection is localized and diagnosed early.^13,16 However, in fulminant cases like ours, hysterectomy is often necessary. Criteria for hysterectomy include hemodynamic instability, failure of medical therapy, or extensive uterine involvement. In our patient, the combination of peritonitis, shock risk, and a large necrotic fibroid mandated definitive surgery. This aligns with systematic reviews noting that hysterectomy is the preferred treatment in severe pyomyoma to rapidly control sepsis. ¹¹

Despite the high prevalence of uterine fibroids in sub-Saharan Africa, only two cases of pyomyoma have been reported from the region to date. ¹¹ And worldwide, only a handful of postpartum pyomyomas have been documented in the literature since 1945. ¹³ Most occurred several days to weeks postpartum. ¹³ In one such case, a patient presented with sepsis due to a spontaneously ruptured pyomyoma; she required a total abdominal hysterectomy for definitive source control. ¹⁷ Conversely, some authors report successful uterine-preserving management when the diagnosis is made early and infection is localized.^12,13 These cases often involve smaller or submucosal fibroids and require skilled surgical or interventional radiology techniques. In women with large fibroids during labour or the early postpartum period, prophylactic antibiotics may be considered in selected high-risk situations, although evidence remains limited and such management should be individualized. ¹²

In our case, laboratory findings reflected severe infection: the patient’s white blood cell count peaked at 20.3×10^3/μL preoperatively and normalized to 8.2×10^3/μL by postoperative day 10. This dramatic improvement after surgery highlights the importance of source control. It is noteworthy that postpartum pyomyoma can masquerade as common conditions, delaying definitive care.^8,12 Early consideration of this diagnosis, especially when imaging reveals a fibroid with abscess-like features, may prompt timely surgical intervention and help prevent morbidity.

This report has several limitations. As a single case report, the findings cannot be generalized to all postpartum patients with fibroids. The diagnosis was made on the basis of clinical presentation, imaging, operative findings, and histopathology, and the causative organism was not microbiologically identified in the manuscript. In addition, the report does not allow assessment of whether earlier detection or prophylactic interventions would have prevented this complication. Finally, long-term maternal outcomes and future fertility implications could not be evaluated within the scope of this report.

Conclusion

Postpartum pyomyoma is an exceedingly rare but life-threatening condition. This case highlights several important clinical lessons. First, clinicians should maintain a high index of suspicion for fibroid infection in postpartum patients with an acute abdomen and sepsis, particularly if no other source is apparent. Second, early advanced imaging can aid diagnosis by revealing a necrotic uterine mass. Finally, definitive management usually requires surgery: while conservative approaches (e.g. antibiotic therapy and drainage or myomectomy) may be attempted in stable patients who wish to preserve fertility, hysterectomy is often required in cases of peritonitis or hemodynamic instability. Timely recognition and intervention can dramatically improve outcomes in this unusual complication.