Case summary and presenting symptoms
A 42-year-old woman presented with a three-year history of intermittent lower abdominal pain and a persistent heavy sensation. She reported an earlier pregnancy during which she felt fetal movements that then suddenly stopped and her abdominal size decreased. She did not seek medical attention at that time. Over months the discomfort progressed into constant pressure and localized pain that ultimately prompted hospital evaluation.
Clinical examination and key imaging findings
Physical examination revealed a firm, fixed mass in the lower abdomen. Urine and serum pregnancy tests were negative. Transabdominal ultrasound showed an empty uterine cavity and a distinct, calcified mass in the peritoneal space. Contrast-enhanced CT scan characterized the lesion as an 18×13 cm calcified structure with recognizable fetal skeletal elements: a cranial vault, vertebral column, ribs and long bones—consistent with a lithopedion (calcified fetus).
Pathophysiology: how a lithopedion forms
A lithopedion forms when an abdominal (extrauterine) pregnancy aborts or the fetus dies and the maternal immune system walls it off. Rather than resorbing, the fetal tissues undergo dystrophic calcification, gradually replacing soft tissues with mineral deposits. The calcified envelope prevents infection and can remain stable for years; in some cases the body encapsulates the structure so effectively that systemic inflammatory markers stay normal and the patient remains oligosymptomatic for prolonged periods.
Why symptoms can be delayed or subtle
Symptoms depend on location and size. Small calcified fetuses may produce no symptoms; larger ones can cause mass effect—abdominal distension, localized pain, constipation, urinary frequency or obstructive symptoms depending on adjacent organs. Scar tissue and adhesions formed around the lithopedion can tether bowel loops or pelvic structures, producing intermittent pain and functional disturbances that may be misattributed to common digestive or gynecologic conditions.
Diagnostic approach and step-by-step workup
1. History: document prior pregnancy signs, timeline of fetal movements stopping, prior pelvic pain or infections.
2. Physical exam: palpate for firm, immobile masses; assess for signs of peritonitis or bowel obstruction.
3. Laboratory tests: pregnancy test (urine/serum), basic inflammatory markers (CBC, CRP) to evaluate active infection or inflammation.
4. Imaging sequence: start with ultrasound to distinguish intrauterine from extrauterine masses. If ultrasound suggests calcified structures or is inconclusive, obtain CT for anatomy and to identify skeletal components; MRI can add soft-tissue detail when required.
5. Multidisciplinary review: involving gynecology, general surgery and radiology to plan management, considering adhesions, expected blood loss, and need for bowel or urinary tract repair.
Treatment options and surgical considerations
Surgery is the definitive treatment for symptomatic lithopedion. Preoperative planning should anticipate dense adhesions between the calcified mass and bowel, bladder or omentum. A laparotomy often facilitates safe dissection of large calcified masses; Laparoscopy may be feasible for smaller, well-circumscribed lesions in expert hands. Prepare for possible bowel resection if the mass invades or erodes intestinal walls. Intraoperative cultures are rarely positive because the calcified shell limits infection risk, but obtain samples if there is purulent material.
Postoperative course and follow-up protocol
Postoperatively monitor for surgical complications (bleeding, infection, ileus). Follow-up includes wound checks and clinical assessment of symptom resolution. Imaging is not routinely required unless complications arise. In the reported case, the patient was discharged and followed for six months; her abdominal pain resolved completely and no late complications occurred.
Incidence, historical context and reported cases
Lithopedion is extremely rare. Historical records cite the first documented case in 1582 and the literature reports roughly 300–350 cases worldwide over several centuries. Most diagnoses occur incidentally or when the patient develops late-onset symptoms. Geographic and access-to-care factors influence detection: delayed or absent prenatal care increases the probability that an extrauterine fetal death will calcify unnoticed.
Key takeaways for dismissed and patients
– Maintain a high index of suspicion when a woman reports prior fetal movements that ceased without medical evaluation and later develops a persistent abdominal mass or unexplained chronic abdominal symptoms.
– Use ultrasound as first-line imaging and proceed to CT or MRI for anatomical delineation when calcification or fetal skeletal structures are suspected.
– Coordinate care between gynecology and general surgery to plan safe removal and to anticipate adhesions or visceral involvement.
– Educate patients that lithopedion formation is a protective, calcifying response and that surgical removal typically resolves symptoms when mass effect is present.
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