Exploring the Evolution of Leiomyomatosis Peritonealis Disseminata: A Longitudinal Study on Malignant Transformation and Potential Biomarkers.

Introduction: Leiomyomatosis peritonealis disseminate (LPD) is an entity with uncertain biological behavior, characterized by multiple smooth muscle intra-abdominal and pelvic nodules that may recur after apparently complete resection. LPD has been predominantly described in childbearing age females. Most case reports with short term follow-up describe this as a benign entity. Only isolated case reports indicate the malignant potential of the disease. A comprehensive collation of cases is lacking in literature.Methods: We present a case of malignant transformation of LPD, confirmed by histology and imaging, occurring over two decades. This patient was originally diagnosed with uterine atypical smooth muscle tumor but developed frank malignancy during follow-up. An increasingly malignant aggressive disease course resulted in ultimate development of liver and lung metastases almost 23 years after original diagnoses, resulting in her demise. A comprehensive literature review was performed, and 213 cases of LPD were described, including the present case. Patients were divided into G1 (reportedly benign), G2 (malignant at presentation), and G3 (malignant transformation).Results: Compared to G1, G2 at presentation were more likely to be symptomatic (73%/88%), larger sized (4.1/8.4 cm), and older aged (38/44). In G1, G2, and G3, the average age was 38.5, 44.3, and 37.5 years, respectively; while the disease specific survival was 100%, 71%, and 40%, respectively. The mean number of surgeries performed in G1, G2, and G3 was 1.6, 1.8, and 3.8, respectively. Hormone receptors were found in 24.4% of cases. The mean reported follow-up time in G1, G2, and G3, respectively, was 44.9, 13.1, and 70.5 months. This suggests with longer follow-up, even apparently benign tumors may develop malignancy. The transformation time to malignancy in G3 was 77.8 months, which is more than the average reported follow-up in G1 (44.9 months).Conclusions: LPD is a potentially malignant condition with long latency prior to transformation. Lifelong surveillance should be considered even in cases originally presumed to be benign. Loss of hormone receptor expression may serve as a marker for this transformation. Circulating Tumor DNA (ctDNA) levels may be associated with development of hematogenous metastases and may be a useful biomarker.