¹⁸F-FDG PET/CT in a Rare Case of Multiple Parasitic Leiomyomas after Laparoscopic Morcellation

A 35-year-old woman presented with a progressively increasing anterior abdominal lump for 2 years, with relatively rapid enlargement in the last 3 months. FNAC from the mass done outside was inconclusive, but suspicious for spindle cell neoplasm. She gave a history of a laparoscopic cholecystectomy 6 years back, as well as some form of infertility surgery 11 years back, after which she had two healthy kids. Before radical surgical excision, a baseline contrast-enhanced whole body ¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) was performed [Figure 1]. The maximum intensity projection positron emission tomography (PET) image (a) showed no focus of abnormal increased ¹⁸F-Fluorodeoxyglucose (¹⁸F-FDG) uptake. Transaxial contrast-enhanced computed tomography (CT) (b) and PET/CT (c) images showed a normal uterus for age (broken arrow). Also noted was a well-defined, moderately enhancing solid nodular lesion measuring 2.5 cm × 2.1 cm in size in the recto-uterine pouch, free from adjacent structures (arrow). Transaxial CT (d) and PET/CT (e), and coronal CT (f) and PET/CT (g) images also demonstrated two other well defined moderately enhancing non ¹⁸F-FDG avid nodular lesions in left lower parietal anterior abdominal, the larger one in subcutaneous plane measuring 4.8 cm × 2.2 cm (arrow) and the smaller one along peritoneal surface measuring 2.9 cm × 1.6 cm (arrowhead). No other abnormality was seen in the rest of the body. Based on ¹⁸F-FDG PET/CT findings, suspicion of multiple parasitic leiomyomas was raised. Review of prior infertility surgery documents showed that she had undergone laparoscopic morcellation for a uterine fibroid, further cementing the diagnosis made on PET/CT. The patient then underwent 3-D wide local excision of the parietal abdominal wall lesions with hernioplasty, along with exploratory laparotomy and removal of the rectouterine space lesion. Histopathology showed well circumcised tumors composed of interlacing fascicles of benign smooth muscle cells with elongated nuclei and moderate cytoplasm, split like blood vessels, and no atypia, suggesting leiomyomas.

Close

Figure 1 The maximum intensity projection positron emission tomography (PET) image (a) showed no focus of abnormal increased 18F-Fluorodeoxyglucose (18F-FDG) uptake. Transaxial contrast-enhanced computed tomography (CT) (b) and PET-CT (c) images showed a normal uterus for age (broken arrow). Also noted was a well-defined, moderately enhancing solid nodular lesion measuring 2.5 cm × 2.1 cm in size in the recto-uterine pouch, free from adjacent structures (arrow). Transaxial CT (d) and PET-CT (e), and coronal CT (f) and PET-CT (g) images also demonstrated two other well defined moderately enhancing non 18F-FDG avid nodular lesions in left lower parietal anterior abdominal, the larger one in subcutaneous plane measuring 4.8 cm × 2.2 cm (arrow) and the smaller one along peritoneal surface measuring 2.9 cm × 1.6 cm (arrowhead). No other abnormality was seen in the rest of the body.

Export to PPT

Uterine leiomyomas are common benign tumors seen in about 20%–30% of women beyond middle age. Extrauterine leiomyomas, such as parasitic leiomyomas, are rare and pose great diagnostic challenges.[1] Laparoscopic morcellation of uterine fibroids is performed for symptomatic uterine leiomyomas when the goal is uterine conservation.[2] Parasitic leiomyoma is an uncommon late complication of laparoscopic morcellation, with a reported incidence of 0.9%.[3] The growth of these parasitic leiomyomas is estrogen-dependent.[4] Use of the contained morcellation method reduces the risk of developing parasitic leiomyomas.[5] Surgical removal, if feasible, is the treatment of choice for symptomatic tumors. PET/CT appearance of uterine and extrauterine leiomyomas is variable, with varying degrees of ¹⁸F-FDG uptake.[67] Familiarity with the imaging pattern of postlaparoscopic morcellation parasitic leiomyomas is essential to avoid misdiagnosis as a more sinister pathology. In this case, ¹⁸F-FDG PET/CT ruled out the possibility of high-grade malignancy and also ruled out metastatic deposits from any other primary tumor.