Lymphangioleiomyomatosis of the Pelvic Lymph Nodes Detected Incidentally During Surgical Staging of Gynecological Malignancies: Comprehensive Clinicopathological Analysis of 17 Consecutive Cases from a Single Institution.

Background/aim: Lymphangioleiomyomatosis (LAM) belongs to the perivascular epithelioid cell tumor (PEComa) family. The relationship between LAM and tuberous sclerosis complex (TSC) is of particular concern in a subset of women with clinically occult LAM involving the pelvic lymph nodes. This study aimed to investigate the clinicopathological features of incidental nodal LAM detected during the surgical staging of gynecological tumors.

Patients and methods: During the study period of 10 years, we identified 17 patients with pelvic nodal LAM that was incidentally detected during surgery for gynecological neoplastic lesions. We conducted immunostaining to assess the diagnostic utility of a panel of PEComa markers.

Results: Two of the 17 patients (11.8%) were diagnosed with TSC before surgery without any pulmonary symptoms. During the follow-up, both patients developed pulmonary and extrapulmonary LAMs. All affected nodes were multiple and unilateral in the pelvic region. The mean nodal size was 5.4 mm, and the mean proportion of the area involved in the LAM was 34.1%. In two patients with TSC, the largest affected node measured 19.3 mm and 7.6 mm, respectively, and the proportion of the area replaced by LAM was 99% and 90%, respectively. The most frequently expressed markers were human melanoma black 45 and cathepsin K, which showed 100% positivity in all the examined cases.

Conclusion: While most small nodal LAMs incidentally discovered during surgery have insignificant prognostic value, larger nodal LAMs occupying most of the nodal parenchyma at reproductive age should raise awareness of pulmonary and extrapulmonary LAMs as well as TSC.