Epithelioid angiomyolipoma: a morphologically distinct variant that mimics a variety of intra-abdominal neoplasms

Elevated 18F-FDG accumulation in a malignant epithelioid angiomyolipoma: a case report and review of literature

Epithelioid angiomyolipoma (EAML) is a tumor with malignant potential, as evidenced by its pathological features. Further investigation into its additional characteristics, particularly in imaging, is of great significance for non-invasive detection methods to understand its malignant potential. In this context, we present a case study of a 47-year-old male patient with a right renal EAML. The patient underwent nephrectomy but subsequently developed liver metastasis. Next-generation sequencing confirmed mutations of tuberous sclerosis 2 (TSC2) in both the primary and metastatic lesions. Consequently, the patient received maintenance treatment with the mTOR inhibitor, everolimus. However, treatment was discontinued after six months due to disease progression. Subsequent 18F-FDG PET/CT imaging revealed a large heterogeneous hypermetabolic mass in the liver, along with two other hypermetabolic metastases near the liver capsule. The patient's prognosis was poor, with indicators such as TSC2 mutation, tumor necrosis, high Ki-67 expression, and α-SMA-negative fibroblasts. Despite reoperation, the patient still succumbed to disease progression. The occurrence of malignant metastatic EAML detected using 18F-FDG PET/CT imaging is infrequent. We conducted a comprehensive review of the relevant literature on 18F-FDG PET/CT imaging for EAML. Notably, this article emphasizes that elevated 18F-FDG uptake in EAML may serve as a novel indicator of malignant EAML.

Spontaneous rupture and hemorrhage of renal epithelioid angiomyolipoma misdiagnosed to renal carcinoma: a case report

BACKGROUND

Renal epithelioid angiomyolipoma is a rare and unique subtype of classic angiomyolipoma, characterized by the presence of epithelioid cells. It often presents with nonspecific symptoms and can be easily misdiagnosed due to its similarity to renal cell carcinoma and classic angiomyolipoma in clinical and radiological features. This case report is significant for its demonstration of the challenges in diagnosing epithelioid angiomyolipoma and its emphasis on the importance of accurate differentiation from renal cell carcinoma and classic angiomyolipoma.

CASE PRESENTATION

A 58-year-old Asian female presented with sudden left flank pain and was initially diagnosed with a malignant renal tumor based on imaging studies. She underwent laparoscopic radical nephrectomy, and postoperative histopathology confirmed the diagnosis of epithelioid angiomyolipoma. The patient recovered well and is currently in good health with regular follow-ups. This case highlights the diagnostic challenges, with a focus on the clinical, radiological, and histopathological features that eventually led to the identification of epithelioid angiomyolipoma.

CONCLUSIONS

Epithelioid angiomyolipoma is easily misdiagnosed in clinical work. When dealing with these patients, it is necessary to make a comprehensive diagnosis based on clinical symptoms, imaging manifestations, and pathological characteristics.

Hepatic perivascular epithelioid cell tumor resembling hepatic adenoma and hepatocellular carcinoma on preoperative imaging: a case report

Perivascular epithelioid cell tumor (PEComa), an uncommon mesenchymal neoplasm, arises from specialized perivascular epithelioid cells exhibiting distinct features of smooth muscle and melanocytic differentiation with unpredictable behavior. PEComa tends to occur more commonly in the uterus and kidneys; its occurrence in the liver is exceedingly rare. We presented a case of a 29-year-old woman with hepatic PEComa and evaluated the tumor with MRI, integrated 18F-fluorodeoxyglucose (FDG), and 68Ga-fibroblast activation protein inhibitor (FAPI) PET/CT scans at presentation. The patient had a history of intermittent utilization of oral contraceptive drugs for several years. An abdominal ultrasound in a physical examination from an outside institution revealed a mass in the liver. A contrast-enhanced abdominal MRI revealed restricted diffusion on diffusion-weighted imaging (DWI) and rapid contrast enhancement and washout patterns in the hepatic lesion, suggesting hepatic adenoma (HA) or hepatocellular carcinoma (HCC). Further assessment was carried out using 18F-FDG and 68Ga-FAPI PET/CT scans. The hepatic lesion was non-FDG avid, whereas increased tracer uptake was observed on the 68Ga-FAPI PET/CT. Subsequently, laparoscopic partial resection of liver segment V was performed. Immunohistochemical analyses demonstrated positive staining for HMB45, Melan-A, and SMA while showing negative results for AFP, glypican-3, hepatocyte, and arginase-1. The results were indicative of a hepatic PEComa diagnosis based on these findings. We also review the current literature on the clinical characteristics, pathological features, and challenges in the diagnosis of hepatic PEComa.

Epitheloid Angiomyolipomas of the Kidney: Rare Renal Tumors Associated With Poor Prognoses

OBJECTIVE

To demonstrate the clinical spectrum and challenges associated with clinical management of epitheloid angiomyolipomas (eAML).

METHODS

We retrospectively reviewed the surgical database of a high-volume tertiary kidney cancer center from 2015 to 2020 to identify cases with a final histological diagnosis of eAML. Descriptive analysis of all cases was conducted.

RESULTS

Five surgical cases of eAMLs were identified. Two of which have had no tumor recurrence since surgery, and three patients passed away due to disease progression.

CONCLUSION

eAML are rare renal tumors which the World Health Organisation (5th Edition, 2022) and International Classification of Diseases for Oncology classify as having unspecified, borderline, or uncertain behavior. Here, we report that can also demonstrate aggressive behavior with fatal consequences. Post-operative follow-up should be recommended for all, with shorter intervals for patients with poor prognostic factors.

♣Evaluation of clinicopathological profiles and development of a risk model in renal epithelioid angiomyolipoma patients: a large-scale retrospective cohort study

BACKGROUND

To identify the malignant potential and prognostic indicators of renal epithelioid angiomyolipoma (eAML), clinicopathological and molecular features as well as the drug efficacy of 67 eAML cases were analyzed.

MATERIALS AND METHODS

Sixty-seven renal eAML patients were enrolled and the immunohistochemical features of these patients were examined. FFPE slides of all patients were re-examined. 21 patients with metastasis received Everolimus 10 mg orally once daily. Responses were evaluated with RECIST criteria by three authors. A risk stratification model was constructed using the following factors: pT3 and pT4, presence of necrosis, mitotic count ≥ 2; the presence of atypical mitoses; severe nuclear atypia, SMA negative, Ki-67 ≥ 10%.

RESULTS

The average percentage of the epithelioid component was 85.6% (range 80-95%). Immunohistochemically, Ki-67 ≥ 10% and negative SMA staining were significantly correlated with malignant characteristics (Ki-67: p < 0.001; SMA: p = 0.001). Survival analysis suggested that pT3-pT4 stage, presence of necrosis, severe nuclear atypia, presence of atypical mitoses, mitotic count ≥ 2, Ki-67 ≥ 10% and negative SMA expression were significantly associated with poorer PFS and OS (p < 0.05). The risk model sufficiently discriminated recurrence/metastasis (AUC = 0.897) and cancer-specific mortality (AUC = 0.932) of renal eAML patients in different risk groups. 21 patients had received Everolimus targeted therapy after recurrence/metastasis. The best response for Everolimus treatment was 8/21 (38.1%) partial responses (PR), 9/21 (42.9%) stable disease (SD) and 4/21 (19.0%) progressive disease (PD).

CONCLUSION

The risk stratification model could well distinguish eAML patients at high risk of recurrence/metastasis. Everolimus targeted treatment showed good efficacy in patients with recurrence/metastasis.

A Non-Invasive Scoring System to Differential Diagnosis of Clear Cell Renal Cell Carcinoma (ccRCC) From Renal Angiomyolipoma Without Visible Fat (RAML-wvf) Based on CT Features

Background

Renal angiomyolipoma without visible fat (RAML-wvf) and clear cell renal cell carcinoma (ccRCC) have many overlapping features on imaging, which poses a challenge to radiologists. This study aimed to create a scoring system to distinguish ccRCC from RAML-wvf using computed tomography imaging.

Methods

A total of 202 patients from 2011 to 2019 that were confirmed by pathology with ccRCC (n=123) or RAML (n=79) were retrospectively analyzed by dividing them randomly into a training cohort (n=142) and a validation cohort (n=60). A model was established using logistic regression and weighted to be a scoring system. ROC, AUC, cut-off point, and calibration analyses were performed. The scoring system was divided into three ranges for convenience in clinical evaluations, and the diagnostic probability of ccRCC was calculated.

Results

Four independent risk factors are included in the system: 1) presence of a pseudocapsule, 2) a heterogeneous tumor parenchyma in pre-enhancement scanning, 3) a non-high CT attenuation in pre-enhancement scanning, and 4) a heterogeneous enhancement in CMP. The prediction accuracy had an ROC of 0.978 (95% CI, 0.956–0.999; P=0.011), similar to the primary model (ROC, 0.977; 95% CI, 0.954–1.000; P=0.012). A sensitivity of 91.4% and a specificity of 93.9% were achieved using 4.5 points as the cutoff value. Validation showed a good result (ROC, 0.922; 95% CI, 0.854–0.991, P=0.035). The number of patients with ccRCC in the three ranges (0 to <2 points; 2–4 points; >4 to ≤11 points) significantly increased with increasing scores.

Conclusion

This scoring system is convenient for distinguishing between ccRCC and RAML-wvf using four computed tomography features.

Clear cell lesions in pathology: Histomorphologic approach to diagnosis

There has been remarkable progress in the field of surgical pathology; however, histomorphology has remained the most important and essential tool of the surgical pathologist in everyday practice till now. It is surprising that the hematoxylin-eosin (H and E) stain, introduced more than a century ago, has still remained the gold standard stain for histological examination and diagnosis of human diseases. Besides different findings or clues observed in histopathology sections like inclusions, granules, grooving, globules, halo, or clearing, which would enable the pathologist to provide a precise and accurate diagnosis; observation of clear cells is one of the important findings and clue for reporting. It may also sometimes lead to difficulties and delays in establishing the diagnosis. It can be focal or extensive and primary or rarely it may be secondary. Clear cell changes may be observed in many non-neoplastic, benign, or malignant tumors of diverse origin. Clear cell tumors contain a preponderance of clear cells. It can be seen in almost all the organs of human body and can be classified according to location or biological behavior. Commonly seen clear-cell tumors are usually malignant and common organs involved are female genital tract, urogenital tract, head and neck areas, central nervous system, skin, and rarely in bone and soft tissues. For approach to clear cell lesions, one has to decide if the change is artifactual, a mimic of clear cell tumors, or a clear cell tumor in reality. Once the mimics and artifactual/degenerative changes have been ruled out, a tumor either primarily of clear cell origin or showing secondary change has to be decided. The tumor next is to be diagnosed as benign/malignant and epithelial/mesenchymal based on morphology.

Unusual Primary Neoplasms of the Adult Liver: Review of Imaging Appearances and Differential Diagnosis

The radiological appearance of common primary hepatic tumors such as hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) is widely recognized. Hepatic masses with unusual histology are occasionally encountered, but seldom suspected on imaging. However, many possess characteristic imaging findings, which when assessed along with the clinical and demographic background and serum tumor markers, may enable a prospective diagnosis. This review attempts to familiarize the reader with the clinicopathological characteristics, imaging manifestations, and differential diagnosis of these unusual liver tumors in adults. Biphenotypic primary liver carcinoma is suspected in masses showing distinct areas of HCC and CCA-type enhancement pattern in cirrhotic livers. Fibrolamellar carcinoma occurs in young individuals without underlying chronic liver disease and shows a characteristic T2-hypointense scar frequently showing calcification. Perivascular epithelioid cell tumors are differentials for any arterial hyperenhancing mass in the noncirrhotic liver, particularly in patients with tuberous sclerosis. Multifocal subcapsular tumors showing target-like morphology, capsular retraction and "lollipop" sign are suspicious for epithelioid hemangioendothelioma. On the other hand, multiple hemorrhagic lesions showing patchy areas of bizarre-shaped arterial phase hyperenhancement are suspicious for angiosarcoma. Primary hepatic lymphoma (PHL) is suspected when patients with immunosuppression present with solitary or multifocal masses that insinuate around vessels and bile ducts without causing luminal narrowing. Intense diffusion restriction and low-level homogeneous or target-like enhancement are also ancillary features of PHL. Primary hepatic neuroendocrine tumor shows uptake on Ga-68 DOTANOC PET/CT. Although a straightforward diagnosis may be difficult in these cases, awareness of the characteristic imaging appearances is helpful in suspecting the diagnosis.

Eosinophilic Renal Cell Tumors With a TSC and MTOR Gene Mutations Are Morphologically and Immunohistochemically Heterogenous: Clinicopathologic and Molecular Study

Eosinophilic renal neoplasms have a wide spectrum of histologic presentations, and several studies have demonstrated a subtype of renal cell carcinomas (RCCs) associated with the tuberous sclerosis complex (TSC)/mammalian target of rapamycin pathway. A review of our institutional archives led to the identification of 18 cases of renal eosinophilic tumors with unusual morphology. Immunohistochemical analysis demonstrated that these could be separated into 3 groups: group 1 had solid architecture and morphology similar to chromophobe RCC but was negative for CK20 and vimentin, and had weak focal staining for CK7 and P504S; group 2 had solid architecture and morphology similar to either renal oncocytoma or chromophobe RCC, eosinophilic variant and had diffuse staining of CK7 and P504S, absent to weak staining of CK20, and negative staining for vimentin; and group 3 had solid, cystic and papillary architecture and was negative for CK7, except for 1 case, along with moderate to strong staining of CK20, P504S, and vimentin. The cases were then sent for next-generation sequencing to determine whether molecular pathogenic variants were present. In group 1, all 3 cases had mutations in TSC2. In group 2, pathogenic variants were identified in 3 genes: TSC1, TSC2, and MTOR. In group 3, genetic alterations and pathogenic variants were identified in TSC1 and TSC2. Our results support TSC/MTOR-associated neoplasms as a distinct group that exhibits heterogenous morphology and immunohistochemical staining.

Monotypic angiomyolipoma of the nasal cavity: An extremely rare cause of nasal mass with recurrent epistaxis

Monotypic angiomyolipoma is usually found in the kidneys and is composed predominantly of epithelioid cells which show positivity for melanocyte and smooth muscle markers. It can pose a diagnostic challenge due to a range of differential diagnosis. We report the second case of monotypic angiomyolipoma of nasal cavity and first from India in a 54-year-old male who presented with a nasal polyp. Grossly the tumor was well circumscribed and un-encapsulated. Microscopy showed a large number of epithelioid cells mixed with a few spindle cells, varying sized blood vessels, and focal areas of adipose tissue. Immunohistochemistry was positive for smooth muscle actin (SMA) and human melanoma black (HMB-45) stains. It is important to identify this tumor as it can sometimes be mistaken for malignancy and only needs endoscopic resection.

Partial nephrectomy can be a successful treatment option for renal epithelioid angiomyolipoma: a case report and literature review

Background

Renal epithelioid angiomyolipoma is a rare tumour which involves kidneys in most cases. It is known for its aggressive behaviour as a significant number of cases have been associated with metastatic epithelioid angiomyolipoma. Usually, radical treatment with systemic therapy is recommended. Only a small number of cases of epithelioid angiomyolipomas have been reported with the standard treatment being radical or partial nephrectomy. We present a  case report showing that partial nephrectomy can be a successful treatment option for renal epithelioid angiomyolipoma. This is the first case of this nature in Lithuania.

Case presentation

In this case, a 40-year-old male with epithelioid angiomyolipoma of the left kidney is presented. In 2012, a cystic left renal mass 40 × 41 mm in size was diagnosed incidentally while performing ultrasound and later confirmed by MRI. Due to the size of the tumour and the possibility of renal cell carcinoma, surgery was scheduled. Left partial nephrectomy was performed successfully. Final pathology report came back with the diagnosis of renal epithelioid angiomyolipoma. The patient had yearly follow-up for six years by CT scan, and neither recurrence nor progression were observed.

Conclusions

Early detection and diagnosis are crucial for treatment as the tumour tends to have malignancy potential. With early diagnosis, partial nephrectomy can be performed with yearly follow-up and no systemic treatment required.

A Primary Adrenal Epithelioid Angiomyolipoma (PEComa) in a Patient with Tuberous Sclerosis Complex: Report of a Case and Review of the Literature

Epithelioid angiomyolipomas (EAMLs) are mesenchymal tumors that are part of the family of the perivascular epithelioid cell neoplasms (PEComas). These tumors portray a potential aggressive behavior with metastatic lesions found in around 30% of reported cases. EAMLs might present sporadically or in association with the tuberous sclerosis complex (TSC). They typically involve the kidneys, liver, and lungs. It is extremely rare for these tumors to arise from other organs. The present report describes an unusual case of an adult patient with a history of TSC who developed EAML of the adrenal gland. Moreover, he presented with metastatic disease to the liver, a feature rarely described. The diagnosis of EAMLs can be challenging as they are hard to distinguish from other adrenal or renal tumors without a thorough histopathologic and immunohistochemical evaluation. Due to the potential aggressive behavior of these malignancies, timely diagnosis is extremely important and has significant therapeutic and prognostic implications.

[Malignant renal epithelioid angiomyolipoma (EAML): about a rare case]

L’angiomyolipome rénal épithélioïde malin (AREM) est une entité pathologique rare longtemps considérée comme lésion hamartomateuse et dont le diagnostic positif est purement immuno-histochimique, microscopiquement, il se caractérise par des cellules mononuclées épithélioïdes a cytoplasme clair présentant des atypies cytonucléaires sévères, et exprimant les marqueurs musculaires lisses et mélanocytaires (HMB 45). Nous rapportons un cas rare d’AREM diagnostiqué après analyse anatomopathologique d’une tumeur retropéritonéale dont l’origine ne pourrait être précisée préalablement par la tomodensitométrie.

Comparison of MRI Features of Epithelioid Hepatic Angiomyolipoma and Hepatocellular Carcinoma: Imaging Data From Two Centers

Introduction: Epithelioid hepatic angiomyolipoma (Epi-HAML) can easily be misdiagnosed as a malignant tumor such as hepatocellular carcinoma (HCC) because of the low-fat content on imaging. We analyzed and compared the magnetic resonance imaging (MRI) features of Epi-HAML and HCC, which would aid in disease diagnosis.

Methods: We included 30 pathologically confirmed patients with Epi-HAML and 80 with HCC, who underwent both MRI unenhanced scan and three-phase contrast-enhanced MRI scan. The clinical and MRI features of the two groups were summarized and analyzed.

Results: Epi-HAML showed significant differences compared to HCC group in terms of clinical features such as sex preference, age, concomitant diseases (hepatitis B and cirrhosis), and elevated plasma alpha-fetoprotein (AFP) (P < 0.001). In addition, there were statistically significant differences between both tumor types with regard to conventional MRI findings such as a solitary tumor (100 vs. 83.8%, P = 0.018), well-defined (93.3 vs. 71.3%, P = 0.027), mild hyperintensity (40.0 vs. 3.7%, P < 0.001) on DWI with high b-value, fat within the tumor (43.3 vs. 8.8%, P < 0.001), and rare necrosis (3.3 vs. 26.3%, P = 0.016). Besides, Epi-HAML displayed significant differences compared to HCC in terms of contrast-enhanced MRI characteristics such as draining hepatic vein (30.0 vs. 3.8%, P < 0.001), portal vein tumor thrombus (0 vs. 13.8%, P = 0.033), hypointensity at delayed phase (70.0 vs. 95%, P = 0.001), intra-tumor vessel at delayed phase (36.7 vs. 10.0%, P = 0.003), pseudocapsule (20.0 vs. 78.8%, P < 0.001), and prolonged enhancement (56.7 vs. 1.2%, P < 0.001).

Conclusion: Epi-HAML frequently occurs in middle-aged women and usually lacks characteristic clinical symptoms. Typically, Epi-HAML presents as an isolated and well-defined tumor with rich vasculature. Specific MRI features such as intra-tumor fat, intra-tumor vessel, draining hepatic vein, prolonged enhancement, and lack of capsule may contribute to a more confident diagnosis of Epi-HAML.

CT features of hepatic epithelioid angiomyolipoma: differentiation from hepatocellular carcinoma in patients with noncirrhotic livers

Background

Hepatic epithelioid angiomyolipoma (HEA) shares some similarities with other hepatic tumors, such as hepatocellular carcinoma (HCC). Thus, establishing a definite diagnosis of HEA based on medical imaging is often difficult. In this study, we evaluated multiphasic computed tomography (CT) imaging to differentiate HEA from HCC in patients with noncirrhotic livers.

Methods

We retrospectively analyzed the clinical and imaging data of both contrast and non-contrast enhanced CT scans from 25 patients with HEA and 50 patients with HCC in noncirrhotic livers. CT features, including lesion position, size, shape, interior content, border, enhancement degree, and enhancement pattern, were independently evaluated by two radiologists. Intratumoral blood vessels, peripheral supply vessels, the early display of the hepatic vein, peripheral abnormal perfusion, peripheral washout sign, pseudocapsule, and portal tumor thrombus were also evaluated. Next, we quantitatively analyzed difference within results of clinical and CT characteristics between the HEA and HCC groups.

Results

The number of female HEA patients is more than male (76% vs. 24%), with a mean age of 49.44±10.33 years (from 30 to 68 years). The majority (64%) of HEA patients were asymptomatic, without hepatitis (88%). On non-contrast enhanced CT, HEA mainly manifested as a round (92%), hypodense mass (100%) with little fat (12%) and rare complications, such as hemorrhage (4%) and calcification (4%). HEA all manifested as an intensely enhanced mass on contrast-enhanced CT. The differences between HEA and HCC were significant in the imaging characteristics of the early display of the hepatic vein (32% vs. 0%, P=0.000), intratumoral blood vessels during the nonarterial phase (36% vs. 8%, P=0.003), washout enhancement (52% vs. 86%, P=0.001), and prolonged enhancement (40% vs. 4%, P=0.000).

Conclusions

Although HEA is an uncommon hepatic tumor, clinical and CT manifestation may be indicative. Clinical and CT characteristics including asymptomatic, non-hepatic, fat-deficient, early display of the hepatic vein, intratumoral blood vessels during the nonarterial phase and prolonged enhancement are selected to improve the recognition of HEA, supporting for a differential diagnosis from HCC.

Malignant potential of epithelioid angiomyolipomas of the liver: A case report and comprehensive review of the literature

Hepatic epithelioid angiomyolipoma (HEAML) is a rare mesenchymal tumor that has been reported to have malignant potential. We herein describe a rare case of atypical HEAML. A 43-year-old Caucasian male patient visited his general practitioner due to a productive cough persisting for >2 months. During evaluation with several imaging tests, a chest computed tomography (CT) incidentally revealed a well-demarcated lesion in the caudate lobe of the liver, sized 7 cm. An abdominal magnetic resonance imaging examination confirmed the findings of the CT. The possibility of hepatocellular carcinoma at that time could not be excluded. Due to inconclusive cross-sectional imaging, the patient underwent left hepatectomy with additional resection of segment I. The patient's postoperative course was uneventful. A diagnosis of 'atypical' HEAML was established in the present case. The majority of HEAMLs are considered to be benign, although there are several reported cases exhibiting malignant behavior, such as tumor growth, presence of atypical cells, recurrence after surgical resection, metastasis and invasive growth into the liver parenchyma and alongside the vessels. From 2000 onwards, 19 cases of malignant hepatic AML have been reported. Malignant transformation is considered to occur mostly in the epithelioid subtype. To that end, when epithelioid or atypical characteristics are identified on preoperative biopsy, resection is indicated due to the high probability of malignancy.

Immunohistochemical Biomarkers of Adrenal Cortical Neoplasms

Careful morphological evaluation forms the basis of the workup of an adrenal cortical neoplasm. However, the adoption of immunohistochemical biomarkers has added tremendous value to enhance diagnostic accuracy. The authors provide a brief review of immunohistochemical biomarkers that have been used in the confirmation of adrenal cortical origin and in the detection of the source of functional adrenal cortical proliferations, as well as diagnostic, predictive, and prognostic biomarkers of adrenal cortical carcinoma. In addition, a brief section on potential novel theranostic biomarkers in the prediction of treatment response to mitotane and other relevant chemotherapeutic agents is also provided. In the era of precision and personalized medical practice, adoption of combined morphology and immunohistochemistry provides a new approach to the diagnostic workup of adrenal cortical neoplasms, reflecting the evolution of clinical responsibility of pathologists.

Two in One: Epithelioid angiomyolipoma within a classic kidney angiomyolipoma - a case report

Background

Epithelioid angiomyolipoma is defined as potentially malignant mesenchymal neoplasm, characterized by proliferating epithelioid cells, whereas classic angiomyolipoma, composed of fat, smooth muscle cells and dysmorphic vessels, is defined as a potentially benign. The usual or classic angiomyolipoma is often found incidentally on imaging studies, relatively easily identified due to the presence of fat, in contrast to the epithelioid angiomyolipoma that can pose diagnostic challenges.

Case presentation

We report a 51-year-old female patient in which an ultrasonography examination showed a solid mass close to the right renal pelvis with hypoechoic and hyperechoic areas. A differential diagnosis of atypical sinus lipomatosis, lipoma and a transitional cell carcinoma was postulated whereas in a subsequent computed tomography a classic angiomyolipoma was postulated. A re-examination by contrast enhanced ultrasound revealed a striking perfusion difference of the hypoechoic and hyperechoic areas. The hypoechoic area showed homogenous and prolonged enhancement whereas the hypoechoic area displayed a marked slower contrast material flooding and a relatively rapid wash out. The histological analysis from the biopsy of the hyperechoic area showed a classic angiomyolipoma, whereas the sample of the hypoechoic central portion revealed an epithelioid angiomyolipoma. A nephrectomy was performed because of the malignant potential of the epithelioid variant of the angiomyolipoma.

Conclusions

A solid kidney mass with two sharply defined parts, one-part compatible with a classical angiomyolipoma and the other being suspected of carcinoma, is rare, but also illustrative and instructive. The combination of different imaging modalities in the work up of a solid renal mass facilitated to discriminate benign from malignant areas.

Expanding the Spectrum of Colonic Manifestations in Tuberous Sclerosis: L-Cell Neuroendocrine Tumor Arising in the Background of Rectal PEComa

Tuberous sclerosis complex (TSC) is an autosomal dominant neurocutaneous condition that predisposes to numerous proliferative lesions, including perivascular epithelioid cell tumors (PEComas), such as lymphangioleiomyomatosis (LAM) and angiomyolipomas, and rare neuroendocrine neoplasms. We describe herein a TSC2-harboring tuberous sclerosis patient manifesting with a synchronous well-differentiated L-cell rectal neuroendocrine tumor and leiomyomatosis-like LAM of the rectum. The background large bowel wall was thickened by confluent nodular areas comprising vessels and spindle-to-epithelioid cells, which are immunoreactive for myoid (smooth muscle actin, muscle specific actin, and desmin) and melanocytic markers (HMB45, Melan-A, microphthalmia transcription factor, and CD117). With the exception of TSC-related pancreatic neuroendocrine tumors, the association between tuberous sclerosis and neuroendocrine neoplasms remains largely unknown in the gastrointestinal tract. Neuroendocrine tumorigenesis in tuberous sclerosis is often linked to inactivating mutations of TSC2 leading to aberrant activation of mammalian target of rapamycin (mTOR) pathway. In this report, we document, for the first time, two foci of L-cell rectal neuroendocrine tumor arising in the setting of tuberous sclerosis, thus broadening the spectrum of TSC-associated endocrine disorders. Moreover, to our knowledge, this is only the second documented case of gastrointestinal leiomyomatosis-like LAM in a patient with tuberous sclerosis. The current case provides further evidence that, similar to pancreatic neuroendocrine tumors, neuroendocrine tumors of the luminal gastrointestinal tract may also be a feature of tuberous sclerosis and can be seen in association with PEComas.

Recommendations for imaging-based diagnosis and management of renal angiomyolipoma associated with tuberous sclerosis complex

Renal angiomyolipomas are found in up to 80% of tuberous sclerosis complex (TSC) patients. Although these tumours are usually asymptomatic, lesions >3 cm in diameter are prone to bleeding and up to 10% of TSC patients may experience a massive and potentially fatal retroperitoneal haemorrhage. Diagnosis can be complicated because of the initial lack of symptoms and the fat-poor content of atypical renal angiomyolipomas. After diagnosis, tumour growth and the emergence of new tumours must be monitored. Treatment with mammalian target of rapamycin (mTOR) inhibitors can reduce tumour size and is indicated in patients with TSC-associated renal angiomyolipomas >3 cm in diameter. Imaging-based assessment of kidney disease is essential to the diagnosis and management of patients with TSC. The aims of imaging studies in this context are to detect and characterize tumours, assess and detect the risk of complications and evaluate the response to treatment, especially in patients treated with mTOR inhibitors. A multidisciplinary expert panel developed a series of recommendations based on current evidence and professional experience for imaging studies in adults and children with TSC-associated renal angiomyolipoma. The recommendations cover radiological diagnosis and follow-up of the classic and atypical or fat-poor TSC-associated renal angiomyolipomas, biopsy indications, minimal requirements for radiological requests and reports and recommended technical features and protocols for computed tomography and magnetic resonance imaging.

Sarcoidosis and adrenal angiomyolipoma - A rare tumor and a rarer coincidence

Angiomyolipoma is a benign mesenchymal tumor occurring in about 0.3 % of the general population. Angiomyolipoma of the adrenal gland is a rare entity, and only 5 cases have been reported so far in English literature. Sarcoidosis is a systemic illness of unknown etiology characterized histologically by non-caseating epithelioid granulomas in the affected tissues. Angiomyolipoma of the adrenal occurring in sarcoidosis is an unusual association with no prior published reports. We describe a case of adrenal angiomyolipoma in a 60 year old female with sarcoidosis. (Sarcoidosis Vasc Diffuse Lung Dis 2017; 34: 81-84).

Epithelioid angiomyolipoma of the liver: a case report

Epithelioid angiomyolipoma (EAML) of liver is a rare neoplasm. Hepatic EAML is often misdiagnosed as other neoplasms such as hepatocellular carcinoma due to non-specific clinical and radiologic features. The morphologic features under microscope and immunohistochemistry staining profile are important in the diagnosis EAML. Here, we report a case of 52-year-old man who found 1.2 cm mass in liver by routine checkup. On the impression of hepatocellular carcinoma, lateral sectionectomy of the liver was done. Microscopically, the tumor is composed of predominant epithelioid cells with vascular component and foamy cells. These cells were positive for HMB45, MelanA, and smooth muscle actin and negative for epithelial membrane antigen. The final diagnosis was hepatic EAML.

TFE3-Expressing Perivascular Epithelioid Cell Neoplasm (PEComa) of the Sella Turcica

We report a primary central nervous system (CNS) perivascular epithelioid cell tumor (PEComa) in a middle-aged female patient. The tumor occurred in suprasellar location with secondary extension into the sella turcica. The patient presented with intracranial hemorrhage and an altered level of consciousness. The tumor had morphologic features matching those of other previously described TFE3-translocated PEComas, including epithelioid morphology, diffuse and strong nuclear immunoreactivity for TFE3, and minimal staining with myoid markers. The TFE3 break-apart FISH testing showed a slight splitting of one of the TFE3 signals in 49.5 % of nuclei. This case illustrates that PEComas should be added to the growing list of mesenchymal tumors that can be encountered in the CNS and specifically in the vicinity of the pituitary gland. The recognition of this entity is of significance given their underlying pathogenesis and possible management implications.

Hepatic epithelioid angiomyolipoma: clinical features and imaging findings of contrast-enhanced ultrasound and CT

AIM

To evaluate the clinical features and imaging findings of epithelioid angiomyolipoma (EAML) on contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT).

MATERIALS AND METHODS

During January 2006 to November 2015, six patients with histopathologically proven hepatic EAML were evaluated using both CECT and ultrasonography. Six patients underwent CEUS and four patients had CECT images. Patients' demographics, clinical presentations, laboratory test results, and imaging appearances were collected and analysed.

RESULTS

Six patients were female, and the mean age was 43.5 years. All hepatic EAMLs were solitary. None of patients had specific symptoms, and laboratory tests were normal in all patients. The maximal diameter of the lesions ranged from 3.1 to 6.5 cm (mean 4.4 cm). Baseline ultrasound revealed that 50% of hepatic EAMLs were hypo-echoic and 50% were mixed echoic. CEUS showed that 100% of the hepatic EAMLs displayed homogeneous hyperenhancement in the arterial phase and 67% (4/6) showed hypo-enhancement in the late phase. On CECT, 100% (4/4) of the neoplasms were significantly hyperenhanced in the arterial phase and washout in the portal phase. There was no recurrence or metastasis after a mean follow-up period of 11.8 months.

CONCLUSION

Hepatic EAML shows similar enhancement patterns to that of hepatocellular carcinoma. It should be considered as a possible differential diagnosis in female patients without viral hepatitis infection.

[Renal epithelioid angiomyolipoma mimicking renal carcinoma]

L'angiomyolipome épithélioide est une forme rare d'angiomyolipome à potentiel malin, considéré récemment par l'OMS comme une entité à part dans la classification des tumeurs rénales. Cette lésion pose un problème dans le diagnostic différentiel avec les carcinomes à cellules claires. Il n'y a pas de critère spécifique clinique ou radiologique caractérisant cette tumeur. L'immunohistochimie en révélant la positivité des cellules épithélioide au marqueur HMB45 est essentielle au diagnostic. Le traitement doit être discuté en concertation pluridisciplinaire.

Aneurysm in a Large Sporadic Renal Angiomyolipoma

Angiomyolipomas (AMLs) are the most common mesenchymal renal neoplasms and are classified as neoplasms of perivascular epithelioid cells (PEComa). AML is usually a benign neoplasm arising most often in the kidney although it has been described in a wide variety of sites. Most patients are adults, and one-third suffer from tuberous sclerosis. We describe a case of renal AML in a 54-year-old Bahraini woman who presented to the Bahrain Defence Force Hospital with right flank pain and hematuria, and who was known to have rheumatoid arthritis but had no cutaneous or other stigmata of tuberous sclerosis. It is the largest AML reported in Bahrain and is also striking for the fact that it contained an intratumoral aneurysm that ruptured causing symptoms leading to the radiological diagnosis of renal mass. Furthermore, the occurrence of an aneurysm in sporadic AML, as in our case, is rare since the large majority tend to be seen in association with tuberous sclerosis.

Evolving Strategies in the Treatment of Tuberous Sclerosis Complex-associated Angiomyolipomas (TSC-AML)

Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic disorder characterized by the development of numerous benign tumors that occur in multiple organ systems throughout the lifetime of the affected individuals. Renal angiomyolipomas occur in up to 80% of TSC patients, and chronic kidney disease from increasing tumor burden is the primary cause of TSC-related mortality. Our review evaluates evidence for localized and systemic therapy in the management of TSC-angiomyolipomas. Urologists or nephrologists experienced in TSC disease should coordinate the care of TSC patients with renal involvement to improve care and reduce costs.

A suggestion for pathological grossing and reporting based on prognostic indicators of malignancies from a pooled analysis of renal epithelioid angiomyolipoma

PURPOSE

Epithelioid angiomyolipoma (EAML) is a rare entity of the kidney. The guideline for grossing and reporting of renal EAML has not been established for Chinese patients. We planned this study to provide some preliminary indicators for draft guidelines of pathological diagnosis among Chinese people.

METHODS

The histopathological characteristics of 11 EAML cases from Cancer Hospital, Chinese Academy of Medical Sciences, were reviewed, and a pooled analysis based on our cases and cases from published articles was performed on the histopathological characteristics and prognosis of 56 Chinese patients with EAML. All the cases met the criteria of the 2004 World Health Organization classification of renal tumors.

RESULTS

The ratio of female to male was 1.2:1 with the mean age of 43.4 in the 11 cases. All the 11 cases were sampled following the guideline of renal cell carcinoma. The mean tumor size was 6.5 cm. Four (36.4 %) cases showed necrosis. Six (54.5 %) cases showed invasive borders. Only one case showed metastases. In pooled analysis of the total 56 cases with EAML, 10 cases (17.9 %) showed adverse prognosis. Tumor size, necrosis and invasive edge showed significant difference between favorite and adverse prognostic groups (P < 0.05).

CONCLUSION

The majority of EAML is benign, and true malignant EAML is rare. The sample of EAML should follow the sample guidelines of renal cell carcinoma with some modifications, emphasizing the presence of necrosis and invading edge. The information of tumor size, necrosis and invasive edge should be included in the diagnostic report of each EAML case.

Epithelioid angiomyolipoma mimicking adrenal cortical carcinoma: A diagnostic pitfall

Epithelioid angiomyolipoma (EAML) is a rare mesenchymal neoplasmic variant of angiomyolipoma characterized by aggressive growth and unpredictable outcome. Cases of local recurrence and distant metastasis have been described. The histopathological diagnosis may be difficult, as EAML often mimics other neoplasms. This is the case report of a 39-year-old male patient with EAML, which was initially diagnosed as adrenal cortical carcinoma, due to the lack of cooperation between clinicians and pathologists.

Concurrent angiomyolipomas and renal cell neoplasms in patients without tuberous sclerosis: a retrospective study

Synchronous renal cell neoplasms (RCNs) and angiomyolipomas (AML) occurring in the same kidney are rare. The aim of this retrospective study is to investigate the incidence and clinicopathological features of concurrent AML and RCN in patients without tuberous sclerosis complex (TSC). Partial and radical nephrectomy specimens with a diagnosis of RCN and AML from 1995 to May 2013 were reviewed. Cases were assessed for histological subtype of AML and RCN, topographic relationship between the AML and the RCN, and clinical characteristics. A total of 565 RCNs and 19 AMLs were identified. Of 19 cases of AML, 9 (47%) were associated with renal tumors. Clear-cell renal cell carcinoma (RCC) was the most common malignancy associated with AML (56%). The mean age of patients with concomitant AML and RCN was higher than the mean age of patients with only AML (58.6 vs 55.5 years). The majority of patients with concomitant AML and RCN were female (78%). All concurrent sporadic AMLs were benign. We identified one case of bilateral clear-cell RCC with concomitant multiple bilateral AMLs in a patient with TSC.

Epithelioid Angiomyolipoma in a Pediatric Patient: Case Report and Review of Literature

We report a case of a 17-year-old girl with tuberous sclerosis complex who underwent partial nephrectomy for a newly discovered 7.5-cm renal mass subsequently determined to be an epithelioid angiomyolipoma, a rare variant of angiomyolipoma that can be confused clinically, radiographically, and pathologically for renal cell carcinoma. Proper diagnosis and treatment are critical, especially in the pediatric patient. This case report and review of literature serve at increasing the awareness of this renal tumor, with its somewhat unpredictable outcome, reviewing the pertinent literature on the topic of epithelioid angiomyolipoma in the clinical setting of tuberous sclerosis complex.

Biomarkers in renal cancer

Treatment options for primary and metastatic renal cancer are increasing. Accurate data from the pathological examination of renal cancer specimens aid clinicians in stratifying patients for surveillance and adjuvant therapies. This review focuses on biomarkers in diagnosis, prognosis and prediction of the biologic behavior of renal tumors which should be recorded in pathology reports and which are under investigation. Special emphasis is given to the use of immunohistochemical markers in differential diagnosis of various renal tumor subtypes. The relevance of cytogenetic and molecular findings is also discussed. The review includes the 2012 International Society for Urological Pathology Consensus conference recommendations.

Renal tumors: diagnostic and prognostic biomarkers

The International Society of Urological Pathology convened a consensus conference on renal cancer, preceded by an online survey, to address issues relating to the diagnosis and reporting of renal neoplasia. In this report, the role of biomarkers in the diagnosis and assessment of prognosis of renal tumors is addressed. In particular we focused upon the use of immunohistochemical markers and the approach to specific differential diagnostic scenarios. We enquired whether cytogenetic and molecular tools were applied in practice and asked for views on the perceived prognostic role of biomarkers. Both the survey and conference voting results demonstrated a high degree of consensus in participants' responses regarding prognostic/predictive markers and molecular techniques, whereas it was apparent that biomarkers for these purposes remained outside the diagnostic realm pending clinical validation. Although no individual antibody or panel of antibodies reached consensus for classifying renal tumors, or for confirming renal metastatic disease, it was noted from the online survey that 87% of respondents used immunohistochemistry to subtype renal tumors sometimes or occasionally, and a majority (87%) used immunohistochemical markers (Pax 2 or Pax 8, renal cell carcinoma [RCC] marker, panel of pan-CK, CK7, vimentin, and CD10) in confirming the diagnosis of metastatic RCC. There was consensus that immunohistochemistry should be used for histologic subtyping and applied before reaching a diagnosis of unclassified RCC. At the conference, there was consensus that TFE3 and TFEB analysis ought to be requested when RCC was diagnosed in a young patient or when histologic appearances were suggestive of the translocation subtype; whereas Pax 2 and/or Pax 8 were considered to be the most useful markers in the diagnosis of a renal primary.

Fatal malignant metastastic epithelioid angiomyolipoma presenting in a young woman: case report and review of the literature

Epithelioid angiomyolipomas (EAMLs) are rare mesenchymal tumors whose malignant variant is extremely uncommon and highly aggressive. Treatment strategies include chemo radiation, transcatheter arterial embolization and surgical resection, which has remained the mainstay treatment. Targeted therapies including mammalian target of rapamycin (mTOR) inhibitors such as Temsirolimus may offer some hope for progressive malignant EAMLs that are not amenable to other treatment modalities. We report a fatal case in a young female who presented with rapidly progressive metastatic EAML that did not respond to mTOR therapy. The literature has shown reduction in tumor burden with the use of mTOR inhibitors, but unfortunately due to the rarity of malignant EAML, a meaningful approach to treatment remains challenging.

Renal epithelioid angiomyolipoma with a negative premelanosome marker immunoprofile: a case report and review of the literature

Introduction

The rare variant of renal epithelioid/pleomorphic angiomyolipoma has been reported in approximately 120 cases. One of the most important characteristics to differentiate these tumors from other renal cell neoplasms is their typical reactivity to premelanosome antigens. If such a tumor does not stain for HMB-45 or Melan-A, a specific diagnosis of epithelioid pleomorphic angiomyolipoma cannot be made with certainty.

Case presentation

We present here what is, to the best of our knowledge, the first case of epithelioid/pleomorphic angiomyolipoma of the kidney in a 50-year-old Caucasian man with no history of tuberous sclerosis, and with a tumor marker profile negative for several premelanosome antigens. The tumor was composed of sheets of pleomorphic, round to polygonal epithelioid cells with prominent eosinophilic cytoplasm, large nuclei, many multinucleated, and very prominent nucleoli. There were prominent vessels and rare interspersed smooth muscle fibers, but adipocytes were not identified. A tumor marker profile showed tumor cell reactivity for CD68, calponin and focally for CD10. Intervening smooth muscle was reactive with smooth muscle actin. The tumor lacked reactivity for melanin-associated antigens HMB-45 and Melan-A, and for CD31, pan-cytokeratin (AE1/3) and desmin. Electron microscopic examination of tumor cells confirmed the presence of premelanosome-like granules.

Conclusions

Based on the characteristic microscopic appearance of this tumor, and its overall tumor marker profile, we concluded this was a renal epithelioid/pleomorphic angiomyolipoma with a negative premelanosome antigen phenotype.

Renal tumors with clear cells. A review

The spectrum of primary renal tumors in which clear cells may appear is revisited in this review. The pathologist's viewpoint of this topic is pertinent because not all the tumors with clear cells are carcinomas and not all renal cell carcinomas with clear cells are clear cell renal cell carcinomas. In fact, some of them are distinct entities according to the new WHO classification. The morphological approach is combined with genetics. Renal cell carcinoma related to von Hippel-Lindau disease is reviewed first because many of the genetic disorders underlying this disease are also present in sporadic, conventional renal cell clear cell carcinomas. Subsequently, conventional renal cell clear cell carcinomas, familial, non von Hippel-Lindau-associated renal cell carcinomas, translocation carcinomas, hereditary papillary renal cell carcinomas, carcinomas associated to tuberous sclerosis and to Birt-Hogg-Dubé syndrome, chromophobe renal cell carcinomas, carcinomas associated with end-stage renal disease, and clear cell tubulopapillary carcinomas are reviewed. Finally, epithelioid angiomyolipoma is also considered in this review.

Molecular therapies for tuberous sclerosis and neurofibromatosis

Neurofibromatosis type 1 (NF1) and tuberous sclerosis complex (TSC) are autosomal-dominant genetic disorders that result from dysregulation of the PI3K/AKT/mammalian target of rapamycin (mTOR) pathway. NF1 is caused by mutations in the NF1 gene on chromosome 17q11.2. Its protein product, neurofibromin, functions as a tumor suppressor and ultimately produces constitutive upregulation of mTOR. TSC is caused by mutations in either the TSC1 (chromosome 9q34) or TSC2 (chromosome 16p.13.3) genes. Their protein products, hamartin and tuberin, respectively, form a dimer that acts via the GAP protein Rheb (Ras homolog enhanced in brain) to directly inhibit mTOR, again resulting in upregulation. Specific inhibitors of mTOR are in clinical use, including sirolimus, everolimus, temsirolimus, and deforolimus. Everolimus has been shown to reduce the volume and appearance of subependymal giant cell astrocytomas (SEGA), facial angiofibromas, and renal angiomyolipomas associated with TSC, with a recent FDA approval for SEGA not suitable for surgical resection. This article reviews the use of mTOR inhibitors in these diseases, which have the potential to be a disease-modifying therapy in these and other conditions.

A case of primary clear cell hepatocellular carcinoma in a non-cirrhotic liver: an immunohistochemical and ultrastructural study

The clear cell variant of hepatocellular carcinoma is a rare entity, occurring at a frequency of less than 10% of hepatocellular carcinoma, with a female prevalence and usually associated with hepatitis C and cirrhosis. We reported a case of primary clear cell hepatocellular carcinoma occurring in a non-cirrhotic liver without history of hepatitis. Our examination included gross pathology, histopathology, immunohistochemistry, special stains, and electron microscopy evaluation. The tumor was composed of sheets of medium-to-large cells with foamy and reticulated cytoplasm and small-to-medium sized nuclei with variably prominent nucleoli. Oil red O stain showed abundant intracellular lipid. Periodic Acid-Schiff stain confirmed the presence of abundant glycogen deposition. Immunohistochemically the tumor cells were positive for Hep Par1, negative for epithelial membrane antigen, steroidogenic factor-1, HMB45, melan A, CK7 and CK20. Electron microscopy study was performed, which was first done in a clear cell hepatocellular carcinoma occurring in a non-cirrhotic liver without elevation of liver function tests. Ultrastructural evaluation of the clear cells showed scarce cellular organelles, cytoplasmic lipid vacuoles and swollen mitochondria.

Pathophysiology and management aspects of adrenal angiomyolipomas

Angiomyolipomas are benign mesenchymal tumours originating from the kidney and adrenals. They are rare tumours that can be sporadic and isolated or occur as a part of tuberous sclerosis. These tumours have a high content in the cells, which is pathognomonic for diagnosis using ultrasonography, computed tomography and magnetic resonance imaging. Atypical angiomyolipomas occur with excessive smooth muscle cells and less adipose tissue, and are sensitive to immunohistochemistry studies. Most of these lesions are detected incidentally but some can cause back and abdominal pains if large in size. Larger lesions are also vulnerable to spontaneous or traumatic rupture, causing large retropertitoneal bleeds. Surgery should be considered as the definitive management for larger lesions to avoid associated complications. There have been no reports of any malignant change being reported in any of the lesions but a long follow-up period is still required, given the unknown clinical progression of these rare tumours.

Everolimus: an mTOR inhibitor for the treatment of tuberous sclerosis

Tuberous sclerosis complex (TSC) is a devastating disease affecting virtually all organ systems of the body and is characterized by multiple hamartomas and neurodevelopmental disorders. The majority of patients with TSC have mutations in TSC1 or TSC2, resulting in constitutive activation of mTOR. Because the pathogenesis of the disease is mTOR hyperactivity, mTOR inhibitors have the potential to treat the underlying cause in TSC patients. Everolimus is the first mTOR inhibitor approved in the USA for the treatment of patients with subependymal giant-cell astrocytomas (SEGAs) associated with TSC. Evidence supports and ongoing studies are evaluating the role of mTOR inhibitors in the treatment of a wide spectrum of disease manifestations, including reduction in tumor volume (SEGAs, renal angiomyolipoma) and improvement in epilepsy, lung function and skin manifestations, including facial angiofibromas. In time, the use of mTOR inhibitors in patients with TSC will likely be very well established.