Extrapulmonary uterine lymphangioleiomyomatosis (LAM) and dysfunctional uterine bleeding: the first presentation of LAM in a tuberous sclerosis complex patient

Abstract

Lymphangioleiomyomatosis (LAM) is a rare disease that typically affects women of childbearing age. It most commonly affects the lungs (P-LAM) but can occasionally occur in extra-pulmonary sites (E-LAM). There is a strong association between LAM and the tuberous sclerosis complex (TSC). We report a case of a 42-year-old female TSC sufferer who presented with dysfunctional uterine bleeding. She was not known to have LAM. An endometrial biopsy revealed a spindled-cell lesion suspicious of leiomyosarcoma, which correlated with cross-sectional imaging. She underwent a hysterectomy that showed a bizarre (symplastic) leiomyomatous endometrial polyp with background uterine LAM. We discuss the clinical and pathological implications of this unusual case of E-LAM and the importance of clinicopathological correlation in TSC sufferers. The association of uterine LAM with TSC is important and LAM should be considered as a differential of dysfunctional uterine bleeding and a benign mimic to uterine leiomyosarcoma in patients with TSC.

Keywords: obstetrics and gynaecology; pathology.

Figure 1

(A,B) Gross macroscopic appearance of the uterus, bisected, showing blue–grey trabeculation of the myometrium, background fibroids and a polyp within the endometrial cavity.

Figure 2

(A,B) H&E stained sections at ×4 magnification (A) and ×20 magnification (B) showing diffuse nodular infiltration of the myometrium by spindled-epitheloid cells with abundant eosinophilic granular, occasionally clear cytoplasm with central vesicular nuclei showing inconspicuous nucleoli. The nodules are surrounded by slit-like vascular channels.

Figure 3

D2-40 immunohistochemistry at ×20 magnification highlighting the endothelial lining of the vascular spaces surrounding the lymphangioleiomyomatosis cell nodules.

Figure 4

HMB-45 immunohistochemistry at ×20 magnification. The lymphangioleiomyomatosis cells show variable positive staining.

Figure 5

Smooth muscle actin (SMA) immunohistochemistry at ×10 magnification. Both the tumour cells and the background myometrium stained positively with SMA.

Figure 6

Desmin immunohistochemistry at ×10 magnification. The background myometrium stained positively with desmin. The tumour cells were negative for desmin.