Huge renal angiomyolipomas in tuberous sclerosis complex

Outcomes of angioembolization and nephrectomy for renal angiomyolipoma associated with tuberous sclerosis complex: a real-world US national study

OBJECTIVE

To examine outcomes of clinical procedures for renal angiomyolipoma associated with tuberous sclerosis complex (TSC) based on US national health claims databases.

METHODS

This retrospective cohort study selected two cohorts of TSC patients, who underwent either embolization or nephrectomy (either partial or complete) for renal angiomyolipoma in the years from 2000 through 2011. Based on claims diagnosis codes, we estimated the prevalence rates of 10 angiomyolipoma-related conditions and 50 embolization- or nephrectomy-related conditions in the pre- and post-baseline periods respectively, and made cross-year and cross-period comparison of these rates with repeated measures analysis methods.

RESULTS

The embolization cohort (N = 4280) and the nephrectomy cohort (N = 3842) had mean baseline ages of 50.7 and 51.7 years with 52.5% and 51.3% males, respectively. After the intervention, the embolization cohort had statistically significant reductions (all p < .05) in gross hematuria (-27.7%), retroperitoneal hemorrhage (-8.4%), and abdominal mass (-6.9%), and increases in hypertension (15.5%), renal mass or unspecified disorder of kidney and ureter (13.8%), anemia (5.1%), and renal insufficiency (3.3%). Similarly, the nephrectomy cohort saw statistically significant reductions (all p < .05) in gross hematuria (-30.6%), flank pain (-7.5%), and abdominal mass (-6.4%), but increases in hypertension (11.9%), renal insufficiency (10.4%), and anemia (7.6%). Embolization was associated with post-procedure increases in renal mass or unspecified kidney/ureter disorder (13.9%), other disorders of kidney and ureter (3.4%), non-acute renal insufficiency (3.1%), flank pain (3.7%), renal insufficiency (3.2%), etc. (all p < .05). Nephrectomy was associated with post-procedure increases in postoperative ileus (5.3%), pain and headache (4.8%), paralytic ileus (3.6%), etc. (all p < .05).

CONCLUSIONS

Both embolization and nephrectomy were effective, but associated with increases in certain angiomyolipoma-related conditions. Further, the embolization effect on gross hematuria, retroperitoneal hemorrhage, and abdominal mass might subside after the intervention year.

Soft tissue tumors of uncertain origin

Many soft tissue tumors of childhood lack obvious differentiation toward a defined mesenchymal tissue type or have a phenotype that does not correspond to any defined normal tissue. These challenging tumors are currently regarded as neoplasms of uncertain differentiation. Nonetheless, there have been great strides in the understanding of their pathologic and genetic features and biologic underpinnings. The application of new genetic information to the pathologic diagnosis among this group of tumors is an emerging area in diagnostic pediatric pathology. This article reviews the clinicopathologic features of tumors of uncertain and/or miscellaneous origin, with an emphasis on the unique aspects of these neoplasms in children and adolescents, use of diagnostic adjuncts, and differential diagnosis.

Targeting the dysregulated mammalian target of rapamycin pathway in organ transplantation: killing 2 birds with 1 stone

Dysregulation and hyperactivation of the mammalian target of rapamycin (mTOR) pathway define the molecular basis of the hamartoma syndromes, including Cowden syndrome, tuberous sclerosis complex (TSC)/lymphangioleiomyomatosis, and Peutz-Jeghers syndrome. Loss of the tumor suppressors phosphatase and tensin homolog (PTEN), TSC1, TSC2, and LKB1 results in uncontrolled growth of usually benign tumors in various organs that, however, frequently lead to organ failure. Therefore, organ transplantation is a common therapeutic option in distinct patients with hamartoma syndromes, especially those with TSC/lymphangioleiomyomatosis. mTOR inhibitors are currently used in allogeneic transplantation as immunosuppressants and for the treatment of a growing number of cancers with dysregulated mTOR/phosphoinositide 3-kinase pathway. This dual targeting provides the unique opportunity for mTOR inhibitors to affect hamartoma syndromes at the molecular level along with potent immunosuppression in transplanted individuals. Here, we review the molecular mechanisms of hamartoma syndromes and discuss the recent clinical progress in transplant patients with hamartomas. Combining the identification of novel molecular targets of the phosphoinositide 3-kinase/mTOR pathway with insights into the clinical effectiveness of current therapeutic strategies sets the stage for a broader translational potential essential for further progress both in the treatment of cancer and for transplantation.

Embolization of giant renal angiomyolipomas: technique and results

PURPOSE

To evaluate the efficacy and safety of prophylactic embolization of angiomyolipomas (AMLs) larger than 10 cm.

MATERIALS AND METHODS

Sixteen patients (mean age, 41.2 years; 14 women and two men) underwent embolization for 23 AMLs larger than 10 cm. All lesions were embolized by using microcatheters with ethanol and ethiodized oil mixed to a ratio of 7(ethanol) to 3(ethiodized oil). Data collected included pre- and posttreatment AML size, creatinine level, technical success, volume of embolic material used, clinical success, and complications.

RESULTS

The mean AML size before treatment was 15 cm (range, 10-25 cm). Ten of the 16 patients (62%) had all their AMLs treated in one session, whereas six (38%) required multiple sessions. A mean volume of 8.6 mL of the ethanol-ethiodized oil mixture (range, 2-20 mL) was administered per lesion. Patients were followed up for a mean of 29 months (range, 1-80 months). No patient had an increase of 0.2 mg/dL (17.7 mumol/L) or greater in mean serum creatinine level during the follow-up period. Two of the 16 patients (12%) required repeat embolization due to AML regrowth (n = 1) or reperfusion (n = 1) seen at surveillance imaging. One of the 16 patients (6.2%) had an AML hemorrhage 59 months after AML embolization.

CONCLUSIONS

Embolization of giant renal AMLs to decrease the risk of bleeding can be done safely without loss of renal function. Although recurrence was infrequent, additional treatment may be necessary and giant renal AMLs should be followed up with serial imaging studies.

More than just a bump: the hamartoma syndromes

The hamartoma syndromes detailed in this review are just a few examples of the many genodermatoses now known to be associated with uncontrolled tumor proliferation secondary to mutations in tumor suppressor genes. Knowledge gained through the study of these syndromes has not only improved our understanding of patients afflicted with such conditions, but has also led to significant insight into the important role tumor suppressor genes play in preventing tumor formation and in carcinogenesis. As major strides continue to be made in the identification of causative mutations in the hamartoma syndromes, options for genetic testing will continue to expand. Identification of mutations in PTEN in the various disorders that compose the PTEN hamartoma tumor syndrome illustrates just how such genetic knowledge has altered the way we both categorize and manage certain genetic conditions. As advances continue to be made in this arena, it is quite conceivable that many of the genetic syndromes will be renamed or categorized based on genetic mutations rather than the characteristic clinical features. However, despite these advances, it will still be the astute clinician's recognition of key clinical features that allows the diagnosis of a hamartoma syndrome to be considered.