Endometrial adenocarcinoma presenting in a premenopausal patient with tuberous sclerosis

Diagnostic management of occult nodal lymphangioleiomyomatosis detected during pelvic cancer staging. Localized finding or systemic disease?

Background

Lymphangioleiomyomatosis (LAM) is a neoplastic disease that generally arises in the lung (pLAM) and may be associated with "Tuberous sclerosis complex" (TSC). Occasionally, LAM can arise at the extrapulmonary sites (eLAM), such as the mediastinum, the retroperitoneum or the lymph nodes. 25-30% of the patients affected by pLAM develop eLAM. In asymptomatic patients, the presence of mediastinal and retroperitoneal eLAM preceded that of pLAM by usually 1-2 years. Nevertheless, some authors reported that the nodal eLAM, detected during pelvic cancer staging, arise in patents without pLAM and/or TSC. In this paper we review the Literature of this rare condition suggesting its diagnostic management.

Results

To date, it has been reported 30 cases. The mean age at diagnosis is 55 years and around 30% of patients are postmenopausal. In only 2 cases was diagnosed a following p-LAM. One patient with endometrioid carcinoma and pelvic nodal eLAM reported TSC2 germiline mutation. None case was associated with both p-LAM and TSC.

Conclusions

The retrospective probability to have p-LAM in patients with staging pelvic nodal e-LAM is 6,6% (4/30) lower than the probability to have e-LAM in patients affected by p-LAM (25-30%). In both this association is more probable sporadically than associated with TSC. The association between cancer staging pelvic nodal e-LAM and TSC is low (3%; 1/30). The p-LAM developed are asymptomatic with a behavior, regardless of hormonal status, similar to lesions diagnosed in postmenopausal although further studies are mandatory to confirm it.

Do patients with tuberous sclerosis complex have an increased risk for malignancies?

Tuberous Sclerosis Complex (TSC) is generally characterized by the presence of benign tumors, but some patients with malignancies have been reported in the literature. We examined a large Italian TSC population (240 individuals followed from 2001 to 2015, aged 3 months-74 years), assessing the frequency of malignancies to determine whether there is an increased risk for cancer in this disorder, and looking for possible features associated with the development of neoplasia. Fifteen patients had malignancies (6.25%); median age at diagnosis was 37.5 years (range of 1.6-58). Five of seven renal tumors were renal cell carcinomas. Eight patients had a non-renal malignancy (3.3%), but we did not find a more prevalent type of cancer. No patient developed more than one malignancy. The prevalence of all malignant tumors was compatible with the prevalence in the general population (5.6%, 95%CI 2.99-9.31%, vs. 4.4% in Italy). Median age at cancer diagnosis was lower (37.5 years, 95%CI 28.6-44.7, vs. 66.0 years). Two patients (13.3%) died of their cancer, while outcome was favorable in the remaining individuals. Malignant tumors were more frequently diagnosed in patients with mutations in TSC1 when compared to TSC2 and patients with no mutation identified (P = 0.032). Our study demonstrated that TSC patients do not seem to have an increased risk for malignancies besides renal cell carcinoma. However, when cancer develops, age at diagnosis is lower than in the general population, and malignant tumors are more frequently diagnosed in patients with mutations in TSC1. Further studies are needed to confirm these data. ©2016 Wiley Periodicals, Inc.

Loss of tuberous sclerosis complex-2 function and activation of mammalian target of rapamycin signaling in endometrial carcinoma

PURPOSE

The involvement of phosphatase and tensin homologue deleted on chromosome ten (PTEN) in endometrial carcinoma has implicated phosphatidylinositol 3-kinase signaling and mammalian target of rapamycin (mTOR) activation in this disease. Understanding the extent of mTOR involvement and the mechanism responsible for activation is important, as mTOR inhibitors are currently being evaluated in clinical trials for endometrial carcinoma. Although tuberous sclerosis complex 2 (TSC2) is the "gatekeeper" for mTOR activation, little is known about defects in the TSC2 tumor suppressor or signaling pathways that regulate TSC2, such as LKB1/AMP-activated protein kinase, in the development of endometrial carcinoma.

EXPERIMENTAL DESIGN

We determined the frequency of mTOR activation in endometrial carcinoma (primary tumors and cell lines) and investigated PTEN, LKB1, and TSC2 defects as underlying cause(s) of mTOR activation, and determined the ability of rapamycin to reverse these signaling defects in endometrial carcinoma cells.

RESULTS

Activation of mTOR was a consistent feature in endometrial carcinomas and cell lines. In addition to PTEN, loss of TSC2 and LKB1 expression occurred in a significant fraction of primary tumors (13% and 21%, respectively). In tumors that retained TSC2 expression, phosphorylation of tuberin at S939 was observed with a high frequency, indicating that mTOR repression by TSC2 had been relieved via AKT phosphorylation of this tumor suppressor. In PTEN-null and LKB1-null endometrial carcinoma cell lines with functional inactivation of TSC2, phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and LY294002 were able to inhibit AKT and mTOR signaling and reverse TSC2 phosphorylation. In contrast, although rapamycin inhibited mTOR signaling, it did not relieve phosphorylation of TSC2 at S939.

CONCLUSIONS

Inactivation of TSC2 via loss of expression or phosphorylation occurred frequently in endometrial carcinoma to activate mTOR signaling. High-frequency mTOR activation supports mTOR as a rational therapeutic target for endometrial carcinoma. However, whereas rapamycin and its analogues may be efficacious at inhibiting mTOR activity, these drugs do not reverse the functional inactivation of TSC2 that occurs in these tumors.