Oncocytic angiomyolipoma of the kidney: a case report

Oncocytoma-Like Angiomyolipoma of the Kidney: A Closer Look into the Clinicopathologic, Immunohistochemical, and Molecular Characteristics of a Rare Entity with Review of the Literature

Introduction. Angiomyolipoma (AML) is a mesenchymal neoplasm that belongs to the perivascular epithelioid cell tumor family (PEComa). AMLs can be subtyped into several patterns dependent on cell type, morphology, and tissue composition. One of the patterns, oncocytoma-like AML is a rare entity with only three cases published in the literature. Case presentation. We present a case of a previously healthy 29-year-old woman who underwent a left partial nephrectomy secondary to a 4.6 cm heterogeneous renal neoplasm. Gross examination demonstrated a well-circumscribed renal mass. Modified Giemsa stain preparation showed oncocytic cells in syncytial pattern with ample granular cytoplasm and round nuclei with prominent nucleoli. Histology assessment showed an oncocytic neoplasm with interspersed adipose tissue. The tumor exhibited tubular architecture with the tubules lined by eosinophilic epithelioid cells with nuclear atypia and prominent nucleoli. Thick blood vessels with emanating epithelioid cells were present. High-grade histology features were not identified. The tumor cells were positive for HMB-45 and SMA and negative for PAX8, keratins, KIT, and vimentin. A diagnosis of oncocytoma-like AML was rendered. Next-generation sequencing (NGS) and RNA fusion were performed. NGS revealed no pathogenic variants and RNA fusion identified no rearrangements. Chromosomal copy number alterations were present in the long arm of chromosome 1 (1p) and chromosome 22. Conclusions. We describe and discuss the clinical, cytomorphologic, histologic, and molecular findings of oncocytoma-like AML, a rare renal neoplasm, and provide a review of the literature.

Laparoscopic Trans-Abdominal Right Adrenalectomy for a Large Primitive Adrenal Oncocytic Carcinoma: A Case Report and Review of Literature

Patient: Male, 48

Final Diagnosis: Adrenal oncocytic carcinoma

Symptoms: Asymptomatic

Medication: —

Clinical Procedure: Transabdominal laparoscopic right adrenalectomy

Specialty: Surgery

Oncocytic Renal Cell Carcinoma with Tubulopapillary Growth Having a Fat Component

We report a rare case of oncocytic renal cell carcinoma (RCC) with tubulopapillary growth in the background of tuberculous end-stage kidney disease. Histology of the renal mass consisted of oncocytic cells forming solid, thin tubules and rare papillae. The tumor had abundant eosinophilic oncocytic cells containing occasional cytoplasmic Mallory body–like hyaline globules and a tiny focus of clear cells with intervening mature fat. Both the oncocytic cells and clear cells were immunoreactive for a-methylacyl-CoA racemase, vimentin, pancytokeratin, and CD10, and negative for transcription factor E3, CD15, human melanoma black 45, and c-kit. Mallory body–like hyaline globules were positive for CAM 5.2 and periodic acid–Schiff with or without diastase. Ultrastructurally, the tumor cells had abundant cytoplasmic mitochondria. The present case is a rare case of oncocytic RCC with tubulopapillary growth pattern. The case is unique in that the tumor was mixed with fat component, which is not common in RCC and thus can lead to misdiagnosis.

t(6;11) renal cell carcinoma (RCC): expanded immunohistochemical profile emphasizing novel RCC markers and report of 10 new genetically confirmed cases

Renal cell carcinomas (RCCs) harboring the t(6;11)(p21;q12) translocation were first described in 2001 and recently recognized by the 2013 International Society of Urological Pathology Vancouver Classification of Renal Neoplasia. Although these RCCs are known to label for melanocytic markers HMB45 and Melan A and the cysteine protease cathepsin K by immunohistochemistry (IHC), a comprehensive IHC profile has not been reported. We report 10 new t(6;11) RCCs, all confirmed by break-apart TFEB fluorescence in situ hybridization. A tissue microarray containing 6 of these cases and 7 other previously reported t(6;11) RCCs was constructed and immunolabeled for 21 different antigens. Additional whole sections of t(6;11) RCC were labeled with selected IHC markers. t(6;11) RCC labeled diffusely and consistently for cathepsin K and Melan A (13 of 13 cases) and almost always at least focally for HMB45 (12 of 13 cases). They labeled frequently for PAX8 (14 of 23 cases), CD117 (10 of 14 cases), and vimentin (9 of 13 cases). A majority of cases labeled at least focally for cytokeratin Cam5.2 (8 of 13 cases) and CD10 and RCC marker antigen (10 of 14 cases each). In contrast to a prior study's findings, only a minority of cases labeled for Ksp-cadherin (3 of 19 cases). The median H score (product of intensity score and percentage labeling) for phosphorylated S6, a marker of mTOR pathway activation, was 101, which is high relative to most other RCC subtypes. In summary, IHC labeling for PAX8, Cam5.2, CD10, and RCC marker antigen supports classification of the t(6;11) RCC as carcinomas despite frequent negativity for broad-spectrum cytokeratins and EMA. Labeling for PAX8 distinguishes the t(6;11) RCC from epithelioid angiomyolipoma, which otherwise shares a similar immunoprofile. CD117 labeling is more frequent in the t(6;11) RCC compared with the related Xp11 translocation RCC. Increased pS6 expression suggests a possible molecular target for the uncommon t(6;11) RCCs that metastasize.

Melanotic xp11.2 neoplasm of the ovary: report of a unique case

We describe a primary ovarian neoplasm, occurring in a 15-year-old female patient, with morphologic, immunohistochemical, and molecular genetic features identical to those of the very rare tumors of the kidney previously described as "melanotic Xp11 translocation renal cancer." This represents, to the best of our knowledge, the first report of a melanotic Xp11 translocation-associated neoplasm arising outside of the kidney. We discuss the relationship of these rare tumors to neoplasms showing perivascular epithelioid cell differentiation, in particular those showing TFE3 rearrangements.

Hepatic epithelioid angiomyolipoma with trabecular growth pattern: a mimic of hepatocellular carcinoma on fine needle aspiration cytology

Epithelioid angiomyolipomas (AMLs) of the liver are rare tumors with imaging and cytologic features overlapping with those of hepatocellular carcinomas. We report the fine needle aspiration and core biopsy findings of an epithelioid AML in the right hepatic lobe of a 32-year-old female with tuberous sclerosis. She had undergone renal transplantation 8 years previously after bilateral nephrectomy for renal AMLs and a 3-cm chromophobe renal cell carcinoma. Hepatocellular carcinoma was suspected during the initial cytologic and histologic examination based on the presence of numerous large polygonal cells with ample finely vacuolated or granular cytoplasm, low nucleocytoplasmic ratio, and mild nuclear pleomorphism in the smears, as well as a distinctive trabecular histologic pattern in the core biopsies. Immunoperoxidase stains showed that the neoplastic cells were negative for cytokeratins and positive for HMB45, Melan-A, and smooth muscle actin, establishing the diagnosis of epithelioid AML. To determine the distinguishing cytomorphologic features between epithelioid AML and HCC, we have compared the cytologic features of 15 cases of hepatic AML reported in the literature, including the present case, to the FNA cytologic findings of 38 consecutive cases of HCC diagnosed at out institution.

Renal epithelioid angiomyolipoma: a study of six cases and a meta-analytic study. Development of criteria for screening the entity with prognostic significance

AIMS

Renal epithelioid angiomyolipoma (EAML) is only described in case reports or in multi-institutional small series. The aim was to report cases seen at our institution and to perform a meta-analysis based on a literature review.

METHODS AND RESULTS

Six EAML cases seen at our institution were reviewed and a meta-analysis performed using cases retrieved from a literature review. There were a total of 69 cases for review. The male:female ratio was 1:3. In the absence of areas of typical AML, useful features in distinguishing EAML from epithelial renal neoplasms include: extreme degree of cytological atypia, histiocytoid appearance, presence of melanocytic pigments, solid architecture with the absence of frequent areas of alveolar pattern, tubulo-papillary formation and scarring. A fatal outcome, distant or lymph node metastasis, venous invasion and local recurrence were considered as adverse events and occurred in 40% of cases over a period of follow-up of 3-60 months (mean 22.5 +/- 18 months). Tumours with an unfavourable outcome showing marked cytological atypia and extensive tumour necrosis were larger (135 +/- 43 mm) than those with a favourable outcome (79 +/- 50 mm) (P < 0.002), and predominantly occurred in men.

CONCLUSIONS

Renal neoplasms with certain unusual features should be investigated immunohistochemically to rule out the possibility of EAML. The frequency of adverse outcome is lower in EAML than in renal cell carcinoma.

Melanotic Xp11 translocation renal cancers: a distinctive neoplasm with overlapping features of PEComa, carcinoma, and melanoma

We describe 2 cases of malignant melanotic epithelioid renal neoplasms bearing TFE3 gene fusions. Both neoplasms occurred in children (an 11-y-old boy and a 12-y-old girl), and presented with disseminated metastatic disease including mediastinal and mesenteric adenopathy. Both neoplasms featured sheets of epithelioid cells with clear to finely granular eosinophilic cytoplasm set in a branching capillary vasculature. The neoplastic cells contained variable amounts of finely brown pigment confirmed to be melanin by histochemical stains. By immunohistochemistry, the neoplastic cells labeled for melanocytic markers HMB45 and Melan A, but not for S100 protein, MiTF, or any epithelial marker (cytokeratins, epithelial membrane antigen), renal tubular marker (CD10, PAX8, PAX2, RCC Marker) or muscle marker (actin, desmin). Both neoplasms demonstrated nuclear labeling for TFE3 protein by immunohistochemistry, and the presence of TFE3 gene fusions was confirmed by TFE3 fluorescence in situ hybridization analysis. These distinctive neoplasms combine morphologic features of perivascular epithelioid cell neoplasms (PEComas), Xp11 translocation carcinoma, and melanoma, though the phenotype most closely approaches PEComa. These neoplasms represent the first documented examples in which TFE3 gene fusions coexist with melanin production, and their identification raises the possibility that TFE3 gene fusions may underlie an aggressive subset of lesions currently classified as PEComa in young patients.

Renal angiomyolipoma: clinicopathologic study of 194 cases with emphasis on the epithelioid histology and tuberous sclerosis association

The majority of renal angiomyolipoma (AML) is sporadic and occasionally it occurs as part of tuberous sclerosis complex (TSC). Epithelioid AML (EAML), an uncommon variant, is considered potentially malignant based on anecdotal case reports. The prognostic significance of epithelioid component in an otherwise typical AML is uncertain. We studied 194 AMLs for the clinicopathologic features of epithelioid and TSC-associated AMLs. Epithelioid component was present in 15 cases (7.7%) with an average amount of 51% (range: 10% to 100%). Histologically, the epithelioid tumor cells were categorized into small, intermediate, and large cell type based on the cell size. Worrisome histologic features were seen in many EAMLs, including coagulative tumor necrosis in 27% (4/15), nuclear atypia in 93% (14/15), mitosis in 47% (7/15), and atypical mitosis in 1 case. All 15 EAML patients had a mean follow-up time of 5.1 years and none had local recurrence or distant metastasis. Sixteen (8.2%) AMLs occurred in patients with definitive TSC. Three histologic features, namely microscopic AML foci, epithelioid component, and epithelial cysts, were present in 10 (62.5%), 4 (25%), and 44% (7/16), respectively, of TSC-associated AMLs, compared with 11 (6.2%), 11 (6.2%), and 6 (3.4%), respectively, in non-TSC-associated AMLs (P value all <0.01). In summary, all 15 cases of EAMLs in our study had benign clinical outcomes despite adverse pathologic features. Epithelioid component, epithelial cysts, and microscopic AML foci are strongly associated with TSC and the presence of all 3 features should raise strong suspicion for TSC.

Adrenocortical oncocytic carcinoma with recurrent metastases: a case report and review of the literature

Background

Adrenal cortex oncocytic carcinoma (AOC) represents an exceptional pathological entity, since only 22 cases have been documented in the literature so far.

Case presentation

Our case concerns a 54-year-old man with past medical history of right adrenal excision with partial hepatectomy, due to an adrenocortical carcinoma. The patient was admitted in our hospital to undergo surgical resection of a left lung mass newly detected on chest Computed Tomography scan. The histological and immunohistochemical study revealed a metastatic AOC. Although the patient was given mitotane orally in adjuvant basis, he experienced relapse with multiple metastases in the thorax twice in the next year and was treated with consecutive resections. Two and a half years later, a right hip joint metastasis was found and concurrent chemoradiation was given. Finally, approximately five years post disease onset, the patient died due to massive metastatic disease. A thorough review of AOC and particularly all diagnostic difficulties are extensively stated.

Conclusion

Histological classification of adrenocortical oncocytic tumours has been so far a matter of debate. There is no officially established histological scoring system regarding these rare neoplasms and therefore many diagnostic difficulties occur for pathologists.

Bilateral massive renal angiomyolipoma concurrent with oncocytoma in tuberous sclerosis complex associated with pulmonary lymphangioleiomyomatosis

We describe a patient with tuberous sclerosis complex and massive bilateral renal angiomyolipomas (AMLs) in association with pulmonary lymphangioleiomatosis, who experienced hemorrhagic shock because of rupture of the left renal AML. She was treated with transarterial embolization, followed by bilateral nephrectomy. The total tumor burden weighed 5800 g, making it the largest AML by weight in published reports. The histopathologic examination revealed concurrent oncocytomas with AMLs in the right kidney, indicating a possible shared mechanism in the pathogenesis of these two disorders. This case also represents a rare, but significant, overlap between renal AML, pulmonary lymphangioleiomatosis, and tuberous sclerosis complex.

Concurrent angiomyolipoma and two oncocytomas in the same kidney

We report on a rare case of synchronous angiomyolipoma (AML) and 2 oncocytomas (OCs) in the same kidney of a 73-year-old woman. During the course of a follow-up for a long-standing staghorn calculus in the left kidney, a 4-cm right suprarenal mass and a small solid nodule adjacent to a cyst in the midportion of the right kidney were radiographically discovered. A radical nephrectomy was performed. The suprarenal tumor was found to be an AML, and the small nodule was an OC (1.5 cm). An additional OC (0.8 cm) elsewhere in the right kidney was also identified. The coexistence of AML and other renal tumors is uncommon. Among reported cases, conventional renal cell carcinoma, possibly reflecting its higher incidence, has been the most common concurrent tumor with AML. Although only rare cases of simultaneous AML and OC have been reported in the literature, it appears that the proportion of OC among concurrent renal tumors with AML is higher than expected based on its frequency among all surgically resected renal neoplasms. Whether there is a pathogenetic association between AML and OC needs to be further investigated.