Malignant epithelioid angiomyolipoma of the kidney in a patient with tuberous sclerosis: an autopsy case report with p53 gene mutation analysis

CT and MRI Findings of Renal Angiomyolipoma With Lung Metastasis: A Case Report and Literature Review

Renal angiomyolipoma has two histological variants: classical and epithelioid. Epithelioid angiomyolipoma is considered as a potential malignant tumor, often leading to recurrence and metastasis, with rapid progression in most of the cases. The lung is one of the most commonly reported sites of metastasis, and pulmonary metastasis of renal angiomyolipoma is usually diagnostic by computed tomography (CT) scans. Here, we report for the first time renal angiomyolipoma with lung metastasis by combining CT and magnetic resonance imaging (MRI).

Primary renal malignant epithelioid angiomyolipoma with distant metastasis: a case report and literature review

Epithelioid angiomyolipoma (EAML) is a rare type of mesenchymal angiomyolipoma with potential malignancy in the kidney that can cause lymph node metastases, local recurrence, and distant metastases. Herein, we describe a case of EAML in the right kidney of a 51-year-old man who was admitted to the hospital with a right abdominal mass. Computed tomography revealed a heterogeneously enhanced mass with blurred margins, which was considered a malignant tumor. A radical nephrectomy was then performed. Two years later, the patient developed liver metastases from EAML and was administered sintilimab combined with bevacizumab. The patient survived after 6 months of follow-up. Histologically, the tumors showed clear boundaries and no obvious capsules. The tumor tissue mainly consisted of epithelioid tumor cells, thick-walled blood vessels, and a small amount of adipose tissue. Tumor cells with lipid vacuoles and acinar areas were large, round, polygonal, eosinophilic, or transparent in the cytoplasm. The enlarged and hyperchromatic nuclei were accompanied by distinct nucleoli and pathological mitosis. These histopathological findings resembled those of renal cell carcinoma, and immunohistochemical analysis was performed. The tumor cells were diffusely positive for HMB45, Melan-A, CK20, vimentin antibodies, and TFE3, suggesting that the tumor originated from perivascular epithelioid cells, excluding renal cell carcinoma. The Ki-67 index was 10%. These histopathological features were observed in liver mass puncture tissues. We also summarized 46 cases of EAML with distant metastasis and explored the clinicopathological features of EAML to improve the treatment of the disease. EAML is often ignored in the clinical setting, leading to metastasis and recurrence. Therefore, EAMLs require long-term follow-up, and timely detection of recurrent disease can improve the prognosis.

Molecular Characterization of Malignant Renal Epithelioid Angiomyolipoma: A Review of Two Cases

OBJECTIVES

Epithelioid angiomyolipoma (EAML, perivascular epithelioid cell tumor) is an uncommon primary renal tumor that may recur or metastasize, although there remain limited data for prediction of these outcomes. Here, we report two cases of renal EAML with molecular testing, adding to the existing literature of potential alterations associated with malignant behavior.

METHODS

Tumors diagnosed as malignant renal EAML were identified, and clinical data, radiology, histology, immunohistochemistry, and molecular testing results were reviewed.

RESULTS

Two cases of malignant renal EAML were identified, both of which demonstrated TSC2 and TP53 mutations. In ATRX, one had a mutation and the other had a variant of uncertain significance. In addition, one patient had a synchronous classic angiomyolipoma that lacked TP53 and ATRX alterations.

CONCLUSIONS

These findings highlight the molecular landscape of malignant renal EAML and expand on the existing literature suggesting a role for TP53 and ATRX alterations in malignant progression of these tumors. The presence of synchronous benign and malignant tumors within the same patient offers a unique opportunity to directly compare the molecular alterations, further supporting the association with aggressive behavior.

p53 aberration and TFE3 gene amplification may be predictors of adverse prognosis in epithelioid angiomyolipoma of the kidney

BACKGROUND

Although epithelioid angiomyolipoma of the kidney has been studied by several groups, the reported prevalence of malignant behavior remains uncertain and there are not yet definitive predictive biomarkers. We evaluated the behavior of renal epithelioid angiomyolipoma in a consecutive series in a single institution and investigated the prognostic value of aberrant p53 expression and TFE3 gene abnormality.

METHODS

We retrospectively reviewed 14 epithelioid angiomyolipomas, most with pure or close to pure epithelioid components, comprising 12 consecutive cases who had attended our institution and two consultation cases. Fluorescence in situ hybridization with TFE3 break-apart probe was performed on 14 cases. The 14 cases were also labeled for p53 and TFE3 by immunohistochemistry. All cases were followed up.

RESULTS

Three of the epithelioid angiomyolipomas were strongly positive for TFE3 and two had a mutant expression of p53. Although no TFE3 gene rearrangement was found, the two tumors with strong TFE3 expression showed TFE3 gene amplification. Follow-up details were available for seven of the 12 consecutive cases: two of them had developed metastases and died (29%), their mean overall survival was 41 months, and both had mutant p53 expression. The two consultation cases with TFE3 gene amplification developed recurrence/metastasis within 1 year after surgery.

CONCLUSIONS

Our series study from a single institution presented the prevalence of malignant behavior in pure epithelioid angiomyolipomas, although the small number of cases with follow-up data greatly reduced the accuracy. p53 may be a prognostic marker for epithelioid angiomyolipoma. Cases with TFE3 gene amplification had poor prognoses.

Frequency, Progression, and Current Management: Report of 16 New Cases of Nonfunctional Pancreatic Neuroendocrine Tumors in Tuberous Sclerosis Complex and Comparison With Previous Reports

Background: Tuberous sclerosis complex (TSC) is a genetic condition that causes benign tumors to grow in multiple organ systems. Nonfunctional pancreatic neuroendocrine tumors (PNETs) are a rare clinical feature of TSC with no specific guidelines outlined for clinical management at this time. Our purpose is to calculate the frequency of nonfunctional PNETs as well as characterize the presentation, current clinical management, and assess the impact of systemic mammalian target of rapamycin (mTOR) on nonfunctional PNETs in TSC.

Methods: This retrospective chart review was performed by a query of the TS Alliance's Natural History Database and the Cincinnati Children's Hospital TSC Database for patients with nonfunctional PNET. Clinical data from these two groups was summarized for patients identified to have a nonfunctional PNET and compared to previously reported cases with TSC and nonfunctional PNETs.

Results: Our calculated frequency of nonfunctional PNETs is 0.65%. We identified 16 individuals, nine males and seven females, with a median age of 18.0 years (interquartile range: −15.5 to 25.5). Just over half (56.3%, n = 9) of the patients provided results from genetic testing. Six had pathogenic variants in TSC2 whereas three had pathogenic variants in TSC1. The average age at PNET diagnosis was 15.0 years (range: 3–46 years). Almost all individuals were diagnosed with a PNET during routine TSC surveillance, 56.3% (n = 9) by MRI, 12.5% (n = 2) by CT, 25% (n = 4) by ultrasound, and 6.2% (n = 1) through a surgical procedure. Follow up after diagnosis involved 68.8% (n = 11) having serial imaging and nine of the sixteen individuals proceeding with surgical removal of the PNET. Eight individuals had a history of using systemic mTOR inhibitors. Tumor growth rate was slightly less in individuals taking an mTOR inhibitor (−0.8 mm/yr, IQR: −2.3 to 2.2) than those without (1.6 mm/yr; IQR: −0.99 to 5.01, p > 0.05).

Conclusions: Nonfunctional PNETs occurred at younger ages in our TSC cohort and more commonly compared to ages and prevalence reported for the general population. PNETs in patients on systemic mTOR inhibitors had lower rates of growth. The outcome of this study provides preliminary evidence supporting the use of mTOR inhibitor therapy in conjunction with serial imaging as medical management for nonfunctional PNETs as an alternative option to invasive surgical removal.

Huge Hepatic Angiomyolipoma Mimicking Low Grade Hepatocellular Carcinoma

A 41-year-old man was diagnosed with a huge symptomatic liver mass and was referred to our hospital for liver biopsy and further evaluation. He presented with right upper quadrant tenderness. Enhanced abdominal computed tomography and magnetic resonance imaging revealed a 12.5-cm relatively well-defined heterogeneous enhancing mass in the right inferior liver with a large exophytic component containing a fat component and progressive delayed enhancement. The patient underwent right inferior sectionectomy. The pathological diagnosis was confirmed as angiomyolipoma, 12.3×9.2×5.0 cm in size, with tumor necrosis in 20% of the tissue. Hepatic angiomyolipoma is known as a benign tumor, but in our case, because of the large tumor size and coagulative necrosis, this tumor had malignant potential; surgical resection was deemed to be appropriate, and close follow-up monitoring was essential postoperatively.

Angiomyolipoma of the kidney: from simple hamartoma to complex tumour

Angiomyolipoma is the most common mesenchymal tumour of the kidney, even if for a long time it has been viewed as a hamartoma rather than a neoplasm. It belongs to a family of neoplasms, named PEComa, characterised by the constant presence of perivascular epithelioid cells that co-express smooth muscle and melanogenesis markers. Angiomyolipoma can occur in patients with tuberous sclerosis, a hereditary syndrome due to the alteration of TSC1 or TSC2 genes, or sporadically. Angiomyolipoma and its variants are indolent tumours; however, some epithelioid angiomyolipomas/pure epithelioid PEComas are aggressive, and criteria for malignancy have been proposed to identify those cases. Although typical angiomyolipoma is a straightforward diagnosis, pathologists should be aware of the wide morphological spectrum of its variants which could be tricky in routine clinical practice and could require immunohistochemical analysis for resolution. The differential diagnosis may range from an inflammatory process (for instance xanthogranulomatous pyelonephritis) to the most common renal cancers and sarcomas. The immunoexpression of melanogenesis markers (HMB45 and Melan-A) and cathepsin K is extremely helpful in the majority of cases. Recently, a subset of epithelioid angiomyolipoma/pure epithelioid PEComa harbouring TFE3 gene fusions has been described, raising questions about its relationship with the family of perivascular epithelioid cell tumour. The activation of the mTOR pathway due to genetic alterations of tuberous sclerosis complex in TSC1 or TSC2 genes in angiomyolipoma has also been reported as well as the subsequent therapeutic implications.

Two case reports and literature review for hepatic epithelioid angiomyolipoma: Pitfall of misdiagnosis

BACKGROUND

Hepatic epithelioid angiomyolipoma (HEAML) is a rare liver disease and is easily misdiagnosed. Enhanced recognition of HEAML is beneficial to the differential diagnosis of rare liver diseases.

CASE SUMMARY

We presented two cases of HEAML in Changzheng Hospital, Naval Medical University, and then collected and analyzed all reports about HEAML recorded in PubMed, MEDLINE, China Science Periodical Database, and VIP database from January 2000 to March 2018. A total of 409 cases of HEAML in 97 reports were collected, with a ratio of men to women of 1:4.84 and an age range from 12 years to 80 years (median 44 years). Among the patients with clinical symptoms mentioned, 61.93% (205/331) were asymptomatic, 34.74% (115/331) showed upper or right upper quadrant abdomen discomfort, while a few of them showed abdominal mass, gastrointestinal symptoms, low fever, or weight loss. The misdiagnosis rate of HEAML was as high as 40.34% (165/409) due to its nonspecific imaging findings. Most of the tumors were solitary and round in morphology, with clear boundaries. Ultrasound scan indicated low echo with internal nonuniformity and rich blood supply in most cases. Computer tomography/magnetic resonance imaging enhanced scan showed varied characteristics. The ratio of fast wash-in and fast wash-out, fast wash-in and slow wash-out, and delayed enhancement was roughly 4:5:1. A definite diagnosis of HEAML depended on the pathological findings of the epithelioid cells in lesions and the expression of human melanoma black 45, smooth muscle actin, melanoma antigen, and actin by immunohistochemical staining. HEAML had a relatively low malignant rate of 3.91%. However, surgical resection was the main treatment for HEAML, due to the difficulty diagnosing before operation.

CONCLUSION

HEAML is a rare and easily misdiagnosed disease, and it should be diagnosed carefully, taking into account clinical course, imaging, pathological ,and immunohistochemical findings.

Evidence for a role of geranylgeranylation in renal angiomyolipoma and renal epithelioid angiomyolipoma

Research on mevalonate kinase deficiency has revealed that it may lead to the development of renal angiomyolipomas (RAMLs). Thus, it was suspected that geranylgeranyl pyrophosphate synthase (GGPPS), a key enzyme in the mevalonate pathway, may be involved in the development of RAMLs. In the present study, the expression of GGPPS in RAMLs and renal epithelioid angiomyolipomas (REAs) was assessed, and paraffin embedded specimens from 60 patients, including 9 cases with REA and 51 cases with RAML, were examined. Immunoreactivity was evaluated semi-quantitatively according to the intensity of staining and the percentage of positively stained cells. The results indicated that GGPPS was predominantly present in the cytoplasm, and REA tissues exhibited higher expression of GGPPS in the cytoplasm compared with RAML tissues. It was also identified that GGPPS was upregulated in TSC2-null cells, and inhibition of GGPPS could induce apoptosis of TSC2-null cells by autophagy. In conclusion, the increased expression of GGPPS in RAMLs and REAs indicated that mevalonate pathways may be involved in disease progression. GGPPS may serve as a potential therapeutic target and the current results may provide a novel therapeutic strategy for RAML and lymphangioleiomyomatosis.

Primary kidney malignant epithelioid angiomyolipoma: Two cases report and review of literature

RATIONALE

Epithelioid angiomyolipoma (EAML) is a subtype of angiomyolipoma with malignant potential. A diagnosis of malignant EAML of the kidney is based on extrarenal metastasis, and predicting early transformation is difficult. To propose criteria for indicators of malignant transformation, herein we report 2 cases and review 17 cases reported in the literature (2000-2017).

PATIENT CONCERNS

Tumor of the kidney was determined in 2 patients, and tissues after nephrectomy were pathologically, histologically, and immunochemically examined.

DIAGNOSIS

Malignant EAML.

INTERVENTION

The 2 present patients were treated with nephrectomy only.

OUTCOMES

Case 1 involved a 48-year-old woman with a 7.5-cm solid mass in the right kidney who underwent nephrectomy. CT detected a mass in the liver after 13 months, which was speculated to be metastasis from the kidney lesion. Case 2 involved a 62-year-old man with a 7-cm cystic solid mass in the left kidney who accepted nephrectomy and at 10 months post-surgery lived with no disease. Both cases presented a large tumor, atypical epithelioid cells, mitotic figures, and necrosis; tested positive for melanocytic markers (HMB45, MelanA).

LESSONS

The literature review of malignant EAML led to the identification of 8 malignant features: size ≥5 cm; metastasis; infiltration; necrosis; ≥50% atypical epithelioid cells; cytologic atypia; atypical mitosis; and vessel invasion. The co-existence of at least 5 of these is proposed to indicate malignant EAML. Features of our 2 new cases of primary malignant EAML of the kidney matched these criteria. Our proposal of criteria for predicting malignant feature, based on 2 new cases and 17 cases in the literature, should aid understanding and avoid misdiagnosis. Nephrectomy is currently the common treatment strategy for malignant EAML, but more effective treatment strategies are needed to provide a better prognosis for patients.

Distinct subcellular localization of E-cadherin between epithelioid angiomyolipoma and triphasic angiomyolipoma: A preliminary case-control study

Epithelioid angiomyolipoma (EAML) is a rare variant of angiomyolipoma (AML). Previous studies have demonstrated that epithelial (E-)cadherin is expressed in two subtypes of AML, EAML and triphasic AML; however, the expression pattern of E-cadherin remains unclear. In the present study, a preliminary case-control study was conducted to determine the expression pattern of E-cadherin between EAML and triphasic AML, the control, focusing on the subcellular localization and expression category of E-cadherin. No significant difference was identified in the age, sex, history of tuberous sclerosis, smoking and alcohol consumption between the two groups (P>0.05). In EAML, 9 patients were categorized as exhibiting a low risk of malignant behavior and the other two were categorized as exhibiting an intermediate or high risk of malignant behavior. The proportion of cases expressing E-cadherin, human melanoma black-45 (HMB45), melanoma antigen recognized by T cells 1 (Mart1/Melan A), smooth muscle actin and progesterone receptor were 95.5 (21/22), 95.5 (21/22), 86.4 (19/22), 77.3 (17/22) and 86.4% (19/22), respectively. E-cadherin was identified to be localized, using staining techniques, in the cell membrane and/or cytoplasm. The subcellular localization of E-cadherin was significantly different between EAML and triphasic AML; the majority of EAML cases revealed membranous and cytoplasmic staining, whereas triphasic AML cases demonstrated cytoplasmic staining (P=0.0093). The expression of E-cadherin may be positively associated with HMB45 (P=0.0044) and Mart1/Melan A (P=0.0049). The results of the present study identified that the subcellular localization of E-cadherin may be different between EAML and the control group of triphasic AML. Additionally, E-cadherin and melanocytic markers may be co-expressed in distinct subtypes of AML. A follow-up study with a large sample size to validate the results of the present study, followed by a mechanistic study based on cell lines to determine any significance, are warranted.

Renal epithelioid angiomyolipoma: Histopathologic review, immunohistochemical evaluation and prognostic significance

Epithelioid angiomyolipoma (EAML) is considered to be a potentially malignant tumor and requires a differential diagnosis from renal cell carcinoma. In this study, we assessed the clinicopathologic features of renal EAML and evaluated the prognostic significance. Among 78 angiomyolipoma (AML) patients, a total of 5 EAMLs were identified, accounting for 6.4% of the total AML cases. The mean age was 41.4 years, and the average tumor size was 12.7 cm in diameter. Association of tuberous sclerosis complex was identified in two cases. One EAML case showed malignant behavior with local recurrence and distant metastasis. The malignant EAML had a larger tumor size, a higher percentage of epithelioid component and atypical epithelioid cells, ≥2 mitoses per 10 high power fields with atypical mitosis, necrosis, extrarenal extension, and carcinoma-like growth pattern. Furthermore, the malignant case revealed p53 immunoreactivity and decreased membranous E-cadherin expression. Pathologic evaluation of adverse prognostic factors will be helpful for risk stratification and prognosis estimation of EAML patients.

PEComa: morphology and genetics of a complex tumor family

Perivascular epithelioid cell tumors, or PEComas, are mesenchymal neoplasms composed of histologically and immunohistochemically distinctive epithelioid or spindle cells, which are immunoreactive for both smooth muscle and melanocytic markers. The cells in PEComas are typically arranged around blood vessels and appear to form the vessel wall, often infiltrating the smooth muscle of small- to medium-sized vessels. Periluminal cells are usually epithelioid and the more peripheral cells are spindle shaped. The cells have small, round to oval nuclei, sometimes with focal nuclear atypia, and clear to eosinophilic cytoplasm, and no counterpart normal cell has been identified. The PEComa "family" now includes angiomyolipoma, pulmonary clear cell "sugar" tumor and lymphangioleiomyomatosis, primary extrapulmonary sugar tumor, clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres, abdominopelvic sarcoma of perivascular epithelioid cells, and other tumors with similar features at various sites that are simply termed PEComa. Some PEComas occur in patients with tuberous sclerosis complex and share the genetic abnormalities. There is a behavioral spectrum from benign to frankly malignant, and histologic criteria have been proposed for assessing malignant potential. The differential diagnosis can include carcinomas, smooth muscle tumors, other clear cell neoplasms, and adipocytic tumors. PEComas constitute a genetically diverse group that includes neoplasms harboring TFE3 gene rearrangements and those with TSC2 mutations, indicating alternative tumorigenic pathways. Recent advances in therapy of malignant PEComas relate to increased knowledge of specific genetic changes and their effects on metabolic pathways that are susceptible to specific interventions. We review PEComas, emphasizing the diagnostic spectrum and recent immunohistochemical and genetic findings.

(18)F-FDG PET/CT in detection of sarcomatous degeneration of renal angiomyolipoma in setting of tuberous sclerosis

Angiomyolipomas (AMLs) of kidneys are one of the common extracranial manifestations of tuberous sclerosis (TSC). AMLs when large may cause life-threatening hemorrhage, but seldom undergo malignant degeneration. We describe the appearance of renal AML degenerated to angiosarcoma on (18)F-flruorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) and contrast-enhanced CT (CECT).

Comprehensive clinical and pathological analysis of aggressive renal epithelioid angiomyolipoma: report of three cases

Renal angiomyolipoma (AML) is recognized as a benign hamartomatous lesion arising in the kidney with no obvious malignant potential. However, epithelioid AML (EAML), a rare variant of AML, is potentially malignant, with aggressive clinical features. It can occur in patients with or without tuberous sclerosis. Because EAML may mimic renal cell carcinoma in imaging studies, differentiation of this tumor from renal cell carcinoma preoperatively is difficult. At times, the lesions may extend into the renal vein and inferior vena cava or metastasize to other organs such as the lung and liver. To clarify the biological nature of EAML, three specific cases that we encountered in clinical practice are analyzed and reported in detail.

Malignant epithelioid angiomyolipoma of the kidney with pulmonary metastases and p53 gene mutation

Angiomyolipoma (AML) is a rare tumor mainly arising in the kidney. Here we report the case of a 55-year-old woman with malignant epithelioid angiomyolipoma with p53 gene mutation. After 7 years from radical nephrectomy of the left kidney, the patient developed multiple lung metastases that showed morphologic features overlapping those of the previously lesion, which was misdiagnosed as renal cell carcinoma. Both renal and pulmonary tumors were reevaluated by immunohistochemical assay, which were showed positive for HMB-45 and p53 protein (95%), but negative for epithelial markers and S-100 protein. A correct diagnosis of malignant epithelioid angiomyolipoma was made on the basis of those results. Meanwhile exon 8 mutation of p53 gene was detected in the renal tumor by microdissection-PCR-SSCP and sequencing technique indicating that p53 gene mutation may play an important role in malignant transformation. The patient was died of respiratory failure after 15 years’ follow-up. This is the second report of renal malignant angiomyolipoma with p53 gene mutation.

A rare case of multi-focal angiomyolipoma affecting the pancreas and liver

Angiomyolipoma (AML) are benign tumours composed of varying amounts of thick-walled dysplastic blood vessels, smooth muscle and mature adipose tissue derived from epithelioid cells. We present a previously unreported occurrence of multi-focal pancreatic and hepatic AMLs in a patient and discuss the diagnostic and management difficulties associated with this rare disease. In addition relevant case studies are also reviewed.

p53 in Pure Epithelioid PEComa

Pure epithelioid PEComa (PEP; so-called epithelioid angiomyolipoma) is rare and is more often associated with aggressive behaviors. The pathogenesis of PEP has been poorly understood. The authors studied p53 expression and gene mutation in PEPs by immunohistochemistry, single-strand conformation polymorphism, and direct sequencing in paraffin material from 8 PEPs. A group of classic angiomyolipomas (AMLs) were also analyzed for comparison. Five PEPs were from kidneys and 1 each from the heart, the liver, and the uterus. PEPs showed much stronger p53 nuclear staining (Allred score 6.4 ± 2.5) than the classic AML (2.3 ± 2.9) ( P < .01). There was no p53 single-strand conformation polymorphism identified in either the PEPs or the 8 classic AMLs. p53 mutation analyses by direct sequencing of exons 5 to 9 showed 4 mutations in 3 of 8 PEPs but none in any of the 8 classic AMLs. The mutations included 2 missense mutations in a hepatic PEComa and 2 silent mutations in 2 renal PEPs. Both the missense mutations in the hepatic PEComa involved the exon 5, one involving codon 165, with change from CAG to CAC (coding amino acid changed from glutamine to histidine), and the other involving codon 182, with change from TGC to TAC (coding amino acid changed from cysteine to tyrosine). The finding of stronger p53 expression and mutations in epithelioid angiomyolipomas might have contributed to their less predictable behavior. However, the abnormal p53 expression cannot be entirely explained by p53 mutations in the exons examined in the PEPs.

Coexistence of Renal Epithelioid Angiomyolipoma and Clear Cell Carcinoma in Patients Without Tuberous Sclerosis

Renal epithelioid angiomyolipoma (EAML) is a rare but distinct variant of angiomyolipoma, closely simulating renal cell carcinoma or sarcoma both clinically and histopathologically. This report presents an unusual case of unilateral simultaneous renal EAML and renal clear cell carcinoma. A 52-year-old man without any sign of tuberous sclerosis had a complaint of 6-month history of pain in left renal area and had macroscopic hematuria twice within the recent 1 month. Computed tomography showed the presence of 2 masses in the upper and lower portion of the left kidney. The patient underwent left radical nephrectomy. Histological examination revealed the upper mass was composed of medium to large epithelioid cells with clear or eosinophilic cytoplasm and numerous giant multinucleated cells. Adult-appearing adipose tissue and coagulative necrosis could also be observed focally in the mass. Immunohistochemically, the tumor cells in the upper mass showed positive reactions to actin, HMB-45, Melan-A, and CD68 but negative reactions to pan-cytokeratin (pan-CK), epithelial membrane antigen, and CD10. However, the lower mass was composed of diffusely monomorphic clear cells with strongly immunoreactive for pan-CK, vimentin, and CD10, whereas without expression for HMB-45 and actin. The patient showed no evidence of recurrence or metastasis during 1-year postoperative following-up period. To the authors’ knowledge, this is the first report of coincidental renal EAML and clear cell carcinoma in the same kidney. Unlike classic triphasic angiomyolipoma, adjuvant therapy after resection should be considered for renal EAML because of its malignant potential, more aggressive behavior and poor prognosis.

Liver angiomyolipomas: a clinical, radiologic, and pathologic analysis of 22 patients from a single center

BACKGROUND

Liver angiomyolipomas (AML) are mesenchymal neoplasms with an uncertain clinical behavior. The spectrum of presentation, imaging and histologic features, and outcomes were analyzed in all patients treated at Memorial Sloan-Kettering Cancer Center.

METHODS

Demographics, disease, pathologic, treatment, and outcome-related variables for consecutive patients were reviewed retrospectively. All imaging studies obtained at presentation were reexamined, categorized, and compared using Fisher and Wilcoxon tests.

RESULTS

Between 1989 and 2010, 238 patients with AML were seen and 22 (9.3%) had liver involvement (exclusive = 17; combined with kidney = 5). The median age was 53 years; 18 were females, and 15 had symptoms. AML was not suspected at initial presentation in any patient. Fat-containing neoplasms on imaging were larger (P = .03), with more heterogeneous enhancement compared with fat-poor neoplasms (P = .001), but none of the imaging/histologic features correlated with outcome. Thirteen patients underwent resection (R0 = 9), 4 were observed, 2 received chemotherapy, 2 embolization, and 1 embolization plus intra-arterial chemotherapy. Two patients treated with R0-resection recurred and 2 treated with chemotherapy progressed, but no patient died of AML-related causes. At a median follow-up of 36 months, 7 patients were free of disease, 13 were alive with disease, 1 died of an unrelated cause, and another was lost to follow-up.

CONCLUSION

AMLs are rare neoplasms with an indolent course in most patients. Subtypes based on fat content are recognized, but clinical behavior does not seem to be different. Recurrence after resection is not associated with disease-related mortality. Resection may be unnecessary in selected asymptomatic patients if the diagnosis can be established definitively.

Epithelioid angiomyolipoma of the kidney

Epithelioid angiomyolipoma (eAMLoma) is an uncommon renal mesenchymal tumor with malignant potential and is frequently associated with tuberous sclerosis (TSC). It is composed of polygonal large-sized tumor cells arranged in an epithelioid manner. Differential diagnosis from renal cell carcinoma (RCC) is often challenging because of its epithelioid morphology. Herein is reported three cases of eAMLoma, involving one in a 28-year-old man with TSC and two in women without TSC (34 and 62 years of age, respectively). The male TSC patient had microscopic conventional AMLomas in the same kidney. All patients were positive for melanoma (reactive with HMB45 antibody, and positive for melan A, tyrosinase and microphthalmia transcription factor) and smooth muscle markers (positive for alpha-smooth muscle-specific actin), but not for epithelial markers (cytokeratin, epithelial membrane antigen). In particular, the translocation RCC is an important differential diagnostic candidate, in terms of the positive reaction with HMB45 and morphological similarity. The present tumor samples did not show any reactivity for transcription factor binding to IGHM enhancer 3 or transcription factor EB, which excluded the possibility of translocation RCC. The possibility of eAMLoma should be evaluated as a diagnostic candidate, especially in cases of renal tumors (i) in young patients; (ii) associated with TSC; or (iii) with an epithelioid morphology and a high nuclear grade.