A tissue microarray-based comparative analysis of novel and traditional immunohistochemical markers in the distinction between adrenal cortical lesions and pheochromocytoma

L, Heredia-Espín M, Arias-Intriago M, Izquierdo-Condoy JS. Pheochromocytoma: an updated scoping review from clinical presentation to management and treatment

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors derived from chromaffin cells, with 80-85% originating in the adrenal medulla and 15-20% from extra-adrenal chromaffin tissues (paragangliomas). Approximately 30-40% of PPGLs have a hereditary component, making them one of the most genetically predisposed tumor types. Recent advances in genetic research have classified PPGLs into three molecular clusters: pseudohypoxia-related, kinase-signaling, and WNT-signaling pathway variants. Specifically, the detection of SDHB-related tumors indicates an increased risk of metastatic disease, which may impact decisions regarding functional imaging in patients with high suspicion of metastasis and influence targeted treatment strategies. Diagnosis of PPGLs primarily relies on biochemical testing, measuring catecholamines or their metabolites in plasma or urine. However, molecular testing, functional imaging, and targeted therapies have greatly enhanced diagnostic precision and management. Personalized treatment approaches based on genetic profiling are becoming integral to the clinical management of these tumors. In South American countries like Colombia, functional imaging techniques such as positron emission tomography/computed tomography (PET/CT) with tracers like 18F-DOPA, 18F-fluorodeoxyglucose (18F-FDG), and 68Ga-DOTA-conjugated somatostatin receptor-targeting peptides (68Ga-DOTA-SST) are used to guide follow-up and treatment strategies. Radionuclide therapy with lutetium-177 DOTATATE is employed for patients showing uptake in 68Ga-DOTA-SST PET/CT scans, while access to 131-MIBG therapy remains limited due to high costs and availability. Recent clinical trials have shown promise for systemic therapies such as sunitinib and cabozantinib, offering potential new options for patients with slow or moderate progression of PPGLs. These advancements underscore the potential of personalized and targeted therapies to improve outcomes in this challenging patient population.

From Nonfunctioning Adrenocortical Cancer to Biochemically Silent Paraganglioma Associated with SDHB Mutation: An Uncommon Presentation of a Patient with a Retroperitoneal Mass

The combination of clinical characteristics and diagnostic exams including imaging, laboratory, and molecular tests help in the differential diagnosis of retroperitoneal lesions. We report a 41-year-old male with a metastatic retroperitoneal lesion with atypical characteristics, displaying pathological findings consistent with both nonsecretory pheochromocytomas/paragangliomas and adrenal cortex carcinoma. The patient was examined for abdominal pain, weight loss, and hypertension. Abdominal computed tomography showed a 21 × 8 × 10-cm right retroperitoneal mass. He was initially diagnosed as pheochromocytoma/paraganglioma (PHEO/PGL). However, the diagnosis was later changed to adrenocortical carcinoma based on histopathological features of the metastatic lesions and the findings of normal urinary levels of catecholamines/metanephrines. Systemic chemotherapy and abdominal radiotherapy were performed, in addition to multiple surgical resections, with no satisfactory response. The indolent course of the disease and minimal impact on the patient's performance status led to a genetic evaluation which resulted in the identification of a germline mutation in the succinate dehydrogenase complex subunit B (SDHB). An immunohistology review of previous slides was consistent with the hypothesis of a neuroendocrine tumor. Forty percent of the patients with PHEO/PGL have an underlying germline mutation. SDHB mutation is frequently associated with metastatic disease and dominant secretion of noradrenaline and/or dopamine. In addition to the metastatic disease, few cases with the mutations can be a biochemically silent PHEO/PGL. We concluded that the patient presented a metastatic abdominal paraganglioma associated with an SDHB mutation and we reinforced the need to perform genetic screening for all adrenal/extra-adrenal lesions characteristic of PHEO/PGL.

Adrenal Oncocytic Pheochromocytoma: Insights From a Challenging Diagnostic Journey

Pheochromocytomas are rare adrenal medulla tumors originating from chromaffin cells, accounting for 10% of primary adrenal neoplasms. Oncocytic variants of pheochromocytomas are rare and have been reported in only 150 cases. This report describes the case of a 60-year-old female who arrived with a non-functional adrenal tumor. This case report emphasizes the importance of a comprehensive histological and immunohistochemical study for diagnosing this rare diagnostic entity and its potential diagnostic pitfalls.

Comparison of INSM1 immunostaining with established neuroendocrine markers synaptophysin and chromogranin A in over 14,000 neuroendocrine and non-neuroendocrine tumors

INSM1 is a transcription factor protein which is increasingly used as an immunohistochemical marker for neuroendocrine differentiation. To determine the prevalence of INSM1 expression in tumors and its expression pattern in normal tissues, tissue microarrays containing 14,908 samples from 117 different tumor types/subtypes as well as 76 different normal tissues were analyzed by immunohistochemistry. INSM1 was positive in 89.2% of 471 neuroendocrine neoplasms (NEN) and in 3.5% of 11,815 non-neuroendocrine neoplasms that were successfully analyzed. At least an occasional weak INSM1 positivity was observed in 59 different non-neuroendocrine tumor entities, of which 15 entities contained at least one case with strong INSM1 staining. A comparison with synaptophysin and chromogranin A staining revealed that in NEN, synaptophysin showed the highest sensitivity (93.3%), followed by INSM1 (89.2%) and chromogranin A (87.5%). In neuroendocrine carcinomas (NEC), sensitivity was highest for INSM1 (88.0%), followed by synaptophysin (86.5%) and chromogranin A (66.4%). If INSM1 was used as an additional marker, the sensitivity for detecting neuroendocrine differentiation in NEN increased from 96.6% (synaptophysin and chromogranin A) to 97.2% (synaptophysin, chromogranin A and INSM1). Our study shows that INSM1 is a useful additional marker for neuroendocrine differentiation with high sensitivity, particularly in NEC.

Inhibin Alpha Expression in Human Tumors: A Tissue Microarray Study on 12,212 Tumors

As a result of its expression in corresponding normal cell types, inhibin alpha (INHA) is used as an immunohistochemical marker for adrenocortical neoplasms and testicular or ovarian sex cord stromal tumors. However, other tumors can also express INHA. To comprehensively determine INHA expression in cancer, a tissue microarray containing 15,012 samples from 134 different tumor types and subtypes was analyzed by immunohistochemistry. INHA positivity was found in 72 of 134 tumor categories, including 26 categories with ≥1 strongly positive case. A moderate to strong INHA positivity was found in 100% of 37 granulosa cell tumors of the ovary, 100% of 43 other sex cord stromal tumors of the ovary/testis, 100% of 31 granular cell tumors, 78.5% of 28 adenomas, 44% of 25 carcinomas of the adrenal cortex, and 46.7% of 15 pancreatic acinar cell carcinomas. At least a weak INHA positivity was seen in <33% of cases of 46 additional tumor entities. In summary, these data support the use of INHA antibodies for detecting sex cord stromal tumors, granular cell tumors, and adrenocortical neoplasms. Since INHA can also be found in other tumor entities, INHA immunohistochemistry should only be considered as a part of any panel for the distinction of tumor entities.

Synaptophysin and chromogranin A expression analysis in human tumors

The expression of the neuroendocrine markers synaptophysin and chromogranin A was analyzed by immunohistochemistry in 14,584 samples from 103 different tumor types and subtypes in a tissue microarray format. At least one of these markers was found to be positive in 96.7% of tumors from various subtypes of neuroendocrine neoplasms. In non-neuroendocrine tumors, synaptophysin and/or chromogranin A staining was seen in 6.3% (n = 584), specifically in 41 of 88 non-neuroendocrine tumor entities. Basal cell carcinomas of the skin (50% positive for chromogranin A alone) and adrenocortical carcinomas (91.7% positive for synaptophysin alone) stood out due to a frequent expression of only one specific marker. A subdivision of non-neuroendocrine neoplasms revealed "neuroendocrine differentiation" most commonly in adenocarcinomas from the female genital tract (18.9%), from pancreatico-/hepato-/biliary tract (15.8%) and the prostate (14.9%) while it was rare in urothelial (1.0%) and squamous cell carcinomas (0.6%). A comparison with clinico-pathological parameters of tumor aggressiveness did not suggest a clinical significance of neuroendocrine marker expression in 204 endometrium cancers, 249 pancreatic adenocarcinomas, 233 gastric adenocarcinomas and 1,182 colorectal adenocarcinomas. Within a cohort of 1,073 breast cancers of no special type, synaptophysin positivity was seen in 4.9% of cases and it was significantly linked to advanced tumor stage (p = 0.0427), high tumor grade (p = 0.0319) and loss of estrogen receptor expression (p = 0.0061) but unrelated to patient outcome. In conclusion, "neuroendocrine differentiation" can be observed in many different tumor types with non-neuroendocrine morphology. Evidence for a statistically significant association (p < 0.0001) between such a "neuroendocrine differentiation" and tumor aggressiveness could not be found.

Extraneuraxial Hemangioblastoma: An Unusual Soft Tissue Neoplasm that Mimics More Common Entities but Carries Distinct Clinical Implications

Hemangioblastoma, one of the characteristic tumors associated with Von Hippel-Lindau (VHL) disease, most often presents in the central nervous system (CNS) but can uncommonly arise in extraneuraxial, or previously referred to as peripheral, locations. Without the clinical context of known VHL disease, hemangioblastoma may not enter the differential for a soft tissue mass outside the CNS. Here, we present two patients with diagnostically challenging extraneuraxial hemangioblastoma to highlight the importance of considering this entity within the differential diagnosis of soft tissue neoplasms containing clear cells and delicate vasculature. We review the relevant diagnostic features, including a suggested immunohistochemical panel, along with the potential associated clinical implications of making this diagnosis. It is recommended that affected patients be offered genetic counseling to assess for underlying VHL disease.

SMARCA4-Deficient Undifferentiated Tumor Diagnosed on Adrenal Sampling

OBJECTIVES

SMARCA4-deficient undifferentiated tumor has distinct clinicopathologic features. We describe our experience with primary diagnosis on adrenal sampling.

METHODS

We collected six SMARCA4-deficient undifferentiated tumors diagnosed on adrenal sampling. Immunostains for SMARCA4, SF-1, inhibin, calretinin, S-100 protein, EMA, and TTF-1 were performed. A control group of 63 primary adrenocortical tumors was also immunostained.

RESULTS

Patients included four men and two women (aged 52-77 years). Five had unilateral adrenal masses and one bilateral (range, 2.4-9.6 cm). Five had pulmonary masses, and one had a midline mediastinal mass. All cases had a monotonous epithelioid appearance and variable rhabdoid morphology. Immunophenotypically, all six cases had loss of nuclear SMARCA4 expression and no staining for SF-1, inhibin, calretinin, or S-100 protein. Variable EMA immunoreactivity was present in four of six cases and focal nuclear TTF-1 expression in one of six. All 63 adrenocortical neoplasms had retained nuclear SMARCA4 expression.

CONCLUSIONS

SMARCA4-deficient undifferentiated tumor may present in the adrenal gland, and this series likely represents metastases from thoracic primaries. Because of the frequent absence of lineage marker expression, knowledge of the characteristic clinical presentation, the rhabdoid morphology, and the typical immunophenotype (loss of SMARCA4/BRG1) allow for appropriate distinction from adrenocortical carcinoma.

NordiQC Assessments of Synaptophysin Immunoassays

This paper is number 8 in a series developed through a partnership between ISIMM and NordiQC with the purpose of reporting research assessing the performance characteristics of immunoassays in an external proficiency testing program.

Significance of Alpha-inhibin Expression in Pheochromocytomas and Paragangliomas

Alpha-inhibin expression has been reported in pheochromocytomas and paragangliomas (PPGLs). We analyzed alpha-inhibin immunohistochemistry in 77 PPGLs (37 pheochromocytomas [PCCs] and 40 paragangliomas) and correlated the results with catecholamine profile, tumor size, Ki-67 labeling index, succinate dehydrogenase B subunit and carbonic anhydrase IX (CAIX) staining, and genetic pathogenesis. PPGLs were classified as pseudohypoxic cluster 1 disease with documented VHL mutation or SDHx mutation or biochemical phenotype, whereas NF1-driven and RET-driven PPGLs and those with a mature secretory (adrenergic or mixed adrenergic and noradrenergic) phenotype were classified as cluster 2 disease. The Cancer Genome Atlas data on INHA expression in PPGLs was examined. Alpha-inhibin was positive in 43 PPGLs (56%). Ki-67 labeling indices were 8.07% and 4.43% in inhibin-positive and inhibin-negative PPGLs, respectively (P<0.05). Alpha-inhibin expression did not correlate with tumor size. Alpha-inhibin was expressed in 92% of SDHx-related and 86% of VHL-related PPGLs. CAIX membranous staining was found in 8 of 51 (16%) tumors, including 1 SDHx-related PCC and all 5 VHL-related PCCs. NF1-driven and RET-driven PPGLs were negative for alpha-inhibin and CAIX. Alpha-inhibin was expressed in 77% of PPGLs with a pseudohypoxia signature, and 20% of PPGLs without a pseudohypoxia signature (P<0.05). PPGLs with a mature secretory phenotype were negative for CAIX. The Cancer Genome Atlas data confirmed higher expression of INHA in cluster 1 than in cluster 2 PPGLs. This study identifies alpha-inhibin as a highly sensitive (90.3%) marker for SDHx/VHL-driven pseudohypoxic PPGLs. Although CAIX has low sensitivity, it is the most specific biomarker of VHL-related pathogenesis. While alpha-inhibin cannot replace succinate dehydrogenase B subunit immunohistochemistry for detection of SDHx-related disease, it adds value in prediction of cluster 1 disease. Importantly, these data emphasize that alpha-inhibin is not a specific marker of adrenal cortical differentiation, as it is also expressed in PCCs.

Adrenal Cortical Rests in the Fallopian Tube: Report of a Case and Review of the Literature

We report an extremely unusual finding discovered incidentally during a routine pathologic evaluation of a fallopian tube, surgically removed on the grounds of ectopic pregnancy. We came across a minute yellowish nodule situated within the wall of the salpinx, which corresponded to ectopic adrenal cortex, as verified by microscopical examination, and coexisted with salpingitis isthmica nodosa. A research of the available English literature on this subject confirmed the rareness of the entity we encountered. This case is presented because of its uniqueness, aiming to raise awareness of a rare condition which is discussed along with potential diagnostic dilemmas, its prognostic significance, and possible complications.

Heterotopic Nodules in the Placenta, an Immunohistochemical Re-evaluation of the Diagnosis of Adrenocortical Heterotopia

BACKGROUND

Rare nodules of heterotopic adrenocortical and hepatic tissue are reported in the placenta. A mechanism for adrenocortical tissue in the placenta has been perplexing, while hepatic tissue is generally considered related to yolk sac primordia. The clear cell morphology of these nodules is similar to the adrenal cortex of the adult; however, the fetal adrenal gland does not usually display clear cells.

METHODS

We stained 9 placental nodules, histologically identical to "adrenocortical" heterotopia of the placenta, to determine whether adrenocortical differentiation could be confirmed. These cases include 3 archival cases initially diagnosed as "adrenocortical" heterotopia.

RESULTS

Immunohistochemical staining with steroid factor-1 (SF-1), HepPar-1, and Arginase-1 showed that these nodules of clear cells are actually hepatic (SF-1 negative, HepPar-1, and Arginase-1 positive). PAS staining suggests that glycogen accumulation is responsible for the clear cytoplasm. In contrast, a nodule of adrenocortical heterotopia near the testis and the adrenal gland from a 38-week-old neonatal autopsy case confirm SF-1 reactivity as expected.

CONCLUSION

We propose that adrenocortical heterotopia in the placenta is a misnomer, and that these subchorionic nodules of clear cells demonstrate hepatic differentiation.

Expectorated metastatic adrenocortical carcinoma: a rare presentation of a rare tumour

A 61-year-old woman who was originally diagnosed with locally advanced adrenocortical carcinoma (ACC) 10 years ago, developed massive haemoptysis while away from the UK. Initial investigations revealed a left upper lobe lesion requiring embolisation. Bronchoscopic evaluation was unsuccessful in identifying an underlying cause, and cytology was suggestive of an inflammatory cause. A rigid bronchoscopy was planned but prior to this the patient coughed up a lump of tissue which was sent for histopathological examination. Morphology and immunohistochemistry were consistent with metastatic ACC. ACC is a rare and aggressive tumour of the adrenal cortex. The histological appearances of ACC are similar to that of a carcinoid tumour, creating diagnostic difficulty given the presumed endobronchial origin of the expectorated material in this case. Accurate clinical information and judicious use of immunohistochemistry were key to making the diagnosis. To the authors knowledge, this is the first described case of expectorated metastatic ACC.

Practical Application of Lineage-Specific Immunohistochemistry Markers: Transcription Factors (Sometimes) Behaving Badly

CONTEXT.—

Transcription factors (TFs) are proteins that regulate gene expression and control RNA transcription from DNA. Lineage-specific TFs have increasingly been used by pathologists to determine tumor lineage, especially in the setting of metastatic tumors of unknown primary, among other uses. With experience gathered from its daily application and increasing pitfalls reported from immunohistochemical studies, these often-touted highly specific TFs are not as reliable as once thought.

OBJECTIVES.—

To summarize the established roles of many of the commonly used TFs in clinical practice and to discuss known and potential sources for error (eg, false-positivity from cross-reactivity, aberrant, and overlap "lineage-specific" expression) in their application and interpretation.

DATA SOURCES.—

Literature review and the authors' personal practice experience were used. Several examples selected from the University Health Network (Toronto, Ontario, Canada) are illustrated.

CONCLUSIONS.—

The application of TF diagnostic immunohistochemistry has enabled pathologists to better assess the lineage/origin of primary and metastatic tumors. However, the awareness of potential pitfalls is essential to avoid misdiagnosis.

Histopathological and genetic characterization of aldosterone-producing adenomas with concurrent subclinical cortisol hypersecretion: a case series

PURPOSE

Aldosterone-producing adenomas with concurrent subclinical cortisol hypersecretion are reported in an increasing number of patients. Five aldosterone-producing adenomas from patients with primary aldosteronism and subclinical hypercortisolism were examined.

THE AIMS OF OUR STUDY WERE

(1) to analyze pathological features and immunohistochemical expression of CYP11B1 (11β-hydroxylase) and CYP11B2 (aldosterone synthase) in these tumors; (2) to investigate somatic mutations involved in adrenal steroid hypersecretion and/or tumor growth.

METHODS

Archival micro-dissected paraffin-embedded slides from tumor specimens were used for histological and molecular studies. Immunohistochemistry was performed using monoclonal anti-CYP11B1 and anti-CYP11B2 antibodies. Cellular composition was determined by examining for known features of zona fasciculata and zona glomerulosa, and immunoreactivity for CYP11B1 and CYP11B2 by McCarty H-score. Spot regions for mutations in KCNJ5, ATP1A1, ATP2B3, CACNA1D, PRKACA, and CTNNB1 gene sequences were evaluated.

RESULTS

Four APAs showed a predominant (≥50%) zona fasciculata-like cell pattern: one tumor had CYP11B1 H-score = 150, no detectable CYP11B2 expression, and harbored a PRKACA p.Leu206Arg mutation (that we have reported previously elsewhere), one had no CYP11B1 expression, CYP11B2 H-score = 40, and no mutations; the remaining two adenomas had high CYP11B1 H-score (160 and 240, respectively) and low CYP11B2 H-score (30 and 15, respectively), with the latter harboring a CTNNB1 p.Ser45Phe activating mutation. One of five aldosterone-producing adenomas had a predominant zona glomerulosa-like pattern, CYP11B1 H-score = 15, CYP11B2 H-score = 180, and no mutations.

CONCLUSIONS

The majority of aldosterone-producing adenomas with concurrent subclinical cortisol hypersecretion were composed mainly of zona fasciculata-like cells, while CYP11B1 and CYP11B2 immunostaining demonstrated clear heterogeneity. In a subset of cases, different somatic mutations may be involved in hormone excess and tumor formation.

Adrenal Rest Tumor of the Liver Preoperatively Diagnosed as Hepatocellular Carcinoma

Background

Hepatic adrenal rest tumors are rare and show similar findings to hepatocellular carcinoma (HCC). It is difficult to distinguish an adrenal rest tumor from HCC due to radiological similarity. We report a case of an adrenal rest tumor in the liver that mimicked HCC radiologically.

Case Presentation

A 67-year-old female was referred to our hospital due to the finding of a hepatic mass. Enhanced computed tomography revealed a 17 mm well-defined tumor that was enhanced in the arterial phase and washed out in the portal and delayed phase in the posterosuperior subsegment of the right hepatic lobe, and HCC was suspected. We performed a subsegmental resection of the liver. Microscopic findings showed that the tumor was composed of pale cells, and tumor cells were aligned in alveolar or fascicular arrangements in a similar manner to features of adrenocortical tissue. Immunohistochemically, the tumor expressed synaptophysin and CD56. The final histopathologic diagnosis in this case was an adrenal rest tumor of the liver.

Conclusions

An adrenal rest tumor is similar to HCC in radiological findings. This hepatic tumor should be added to the list of radiological differential diagnoses of hypervascular hepatic tumors.

A Rare Case of Functioning Adrenocortical Oncocytoma Presenting as Cushing Syndrome

Functioning adrenocortical oncocytoma is very rare neoplasm. It is usually nonfunctional and benign and incidentally detected. Generally, these tumors originate in the kidneys, thyroid, parathyroid, and salivary or pituitary glands; they have also been reported in other sites including choroid plexus, respiratory tract, and larynx. Histologically, they are characterized by cells with eosinophilic granular cytoplasm and numerous packed mitochondria. We reported a case of a 44-year-old female who presented with Cushing syndrome for hypersecretion of cortisol due to adrenocortical oncocytoma. Magnetic resonance of abdomen revealed a right adrenal mass. Laparoscopic adrenalectomy was performed and the tumor was pathologically confirmed as benign adrenocortical oncocytoma. After surgical treatment, Cushing's syndrome resolved.

15 YEARS OF PARAGANGLIOMA: Pathology of pheochromocytoma and paraganglioma

Pathologists using their routine diagnostic tools can contribute both to the care of patients with pheochromocytoma/paraganglioma and to understanding the pathobiology of the tumors. They can document details of tissue organization and cytology that are accessible only by microscopy and can characterize admixtures of cell types that are morphologically distinct or show differential expression of immunohistochemical markers. Current roles and challenges for pathologists include differential diagnosis, identifying clues to the presence of hereditary disease, and effective communication of pathology information for clinical and research purposes. Future roles will increasingly involve risk stratification, identification of actionable targets for personalized therapies, and aiding the interpretation of molecular tests by helping characterize genetic variants of unknown significance. It remains to be determined to what extent the need for pathology input will be overshadowed by the availability of genetic testing and other molecular analyses at ever-decreasing cost, together with very effective clinical paradigms for risk stratification and patient care.

Metastatic carcinoma of unknown primary: diagnostic approach using immunohistochemistry

Carcinoma of unknown primary origin (CUP) is one of the 10 most prevalent malignancies. CUP patients in whom a site of origin can be ascribed have better outcomes than those in which the primary tumor remains unidentified. Among the tools available to pathologists in approaching these lesions, immunohistochemistry is a reliable, inexpensive, and widely available resource. New markers continue to emerge, which, in combination with other historically useful antibodies, allow rapid and accurate identification of primary site in an increasing number of cases. This review discusses the approach to the diagnosis of CUP using immunohistochemistry and outlines some of the most useful markers with a particular focus on the utility of lineage-restricted transcription factors, including CDX2, NKX3-1, PAX8, SATB2, TTF-1, and SF1.

Cytologic diagnosis of adrenal oncocytic pheochromocytoma in a lung cancer patient: Report of a case and review of the literature

Adrenal oncocytic pheochromocytoma is an extremely rare type of pheochromocytoma. To the best of our knowledge, we present the first cytological diagnosis of this variant via fine-needle aspiration in an 81-year-old male patient who was found to have an adrenal mass while undergoing workup of the recently diagnosed lung adenocarcinoma. We describe the cytomorphologic findings in our case and provide a review of the reported cases of adrenal oncocytic pheochromocytoma – all of which appear to be benign, nonfunctional, occur in adults, and have similar morphologic features. The pathologist should be aware of this uncommon diagnostic entity and its potential diagnostic pitfalls.

Value of calretinin immunostaining in diagnostic pathology: a review and update

Calretinin is a member of the EF-hand family of calcium-binding proteins. Because its expression is highly restricted to mesotheliomas, calretinin is, at present, the most commonly used positive mesothelioma marker that is most often recommended to be included in the various immunohistochemical panels used to assist in the differential diagnosis of these tumors. Calretinin expression has also been reported to be commonly expressed in a wide variety of other neoplasms, including sex cord-stromal tumors, adrenal cortical neoplasms, olfactory neuroblastomas, Schwann cell tumors, cardiac myxomas, and ameloblastomas. This article reviews the information that is currently available on calretinin expression in tumors and on its application as an immunohistochemical marker in diagnostic pathology.

Immunohistochemical distinction of metastases of renal cell carcinoma to the adrenal from primary adrenal nodules, including oncocytic tumor

Metastases of clear cell renal cell carcinoma to the adrenal can mimic primary adrenal cortical neoplasms or normal adrenal, especially in biopsy material. We compared 34 cases of clear cell renal cell carcinoma metastasis to the adrenal with 49 primary adrenal lesions (16 carcinoma, 22 adenoma, 9 oncocytic tumor, and 2 hyperplasia). Normal adrenal was available in 59 cases. Each entity was represented on tissue microarrays by duplicate-triplicate evaluable spots taken from spatially separate areas. Two pathologists evaluated all reactivity from 0 to 3+. A panel of 12 immunohistochemical stains was performed, including the first diagnostic uses of steroid receptor coactivator (SRC1) and equilibrative nucleoside transporter 1 (ENT1). The most sensitive and specific renal cell carcinoma markers were membranous reactivity for carbonic anhydrase IX (CAIX) and RCC marker and nuclear reactivity for PAX8. For adrenal cortical carcinomas, best markers were synaptophysin, SRC1, and MelanA; and for adrenal oncocytic tumor, synaptophysin and ENT1. Optimal markers for adrenal cortical adenoma and normal adrenal were ENT1 (more specific) and either MelanA or SRC1 (more sensitive). Calretinin, cytokeratin 34βE12 and CAM5.2, inhibin, and steroidogenic factor 1 (SF1) proved less valuable to the panel. Nonspecific cytoplasmic biotin reactivity was frequent for CAIX and PAX8. Tumors with high-grade cytology should be worked up with 2 of the 3 stains: CAIX, PAX8, or RCC marker; and either SRC1 or MelanA. Adrenal adenoma, or normal adrenal, versus low-grade renal cell carcinoma are distinguished by a panel of: CAIX, PAX8, or RCC Marker; ENT1 and either SRC1 or MelanA.

Hepatic adrenal rest tumor: Diagnostic pitfall and proposed algorithms to prevent misdiagnosis as lipid-rich hepatocellular carcinoma

We present a case of adrenal rest tumor of the liver in which differential diagnosis from lipid rich-hepatocellular carcinoma (HCC) was challenging. The patient was a 50-year-old woman in whom a 3-cm tumorous mass was discovered in segment 7 of the liver during computed tomography evaluation of a uterine leiomyoma. The preoperative diagnosis was HCC, and subsegmental liver resection was performed. The tumor appeared as a well-demarcated golden yellow nodule consisting of clear or partially eosinophilic cells arranged in a trabecular pattern. The initial impression of this lesion was that of clear cell type or lipid-rich type HCC because it stained positive for Hep Par1, but negative for arginase-1 and positive for CD56 which is one of the neuroendocrine markers. The lesion also stained positive for SF-1 and 3β-HSD, both of which are markers of adrenocortical tissue. The final diagnosis was hepatic adrenal rest tumor. Hepatic adrenal rest tumor should be considered in the differential diagnosis of segment 7 tumor. A diagnostic algorithm that includes immunohistochemical staining for CD56 and arginase-1 is to rule out the possibility of lipid-rich HCC.

Germline PRKACA amplification leads to Cushing syndrome caused by 3 adrenocortical pathologic phenotypes

We describe the pathology of 5 patients with germline PRKACA copy number gain and Cushing syndrome: 4 males and 1 female, aged 2 to 43 years, including a mother and son. Imaging showed normal or slightly enlarged adrenal glands in 4 patients and a unilateral mass in the fifth. Biochemically, the patients had corticotropin-independent hypercortisolism. Four underwent bilateral adrenalectomy; unilateral adrenalectomy was performed in the patient with the adrenal mass. Pathologically, 3 patients, including the 1 with the tumor (adenoma), had primary pigmented nodular adrenocortical disease with extranodular cortical atrophy and mild intracapsular and extracapsular extension of cortical cells. The other 2 patients had cortical hyperplasia and prominent capsular and extracapsular micronodular cortical hyperplasia. Immunoperoxidase staining revealed differences for synaptophysin, inhibin-A, and Ki-67 (nuclei) in the atrophic cortices (patients 1, 2, and 3) and hyperplastic cortices (patients 4 and 5) and for Ki-67 (nuclei) and vimentin in the extracortical nodules in the 2 groups of patients. β-Catenin stained the cell membrane, cytoplasm, and nuclei of the adenoma. The patients were well at follow-up (1-23 years); 24-hour urinary cortisol excretion was elevated in the patient who had unilateral adrenalectomy.

Adrenocortical carcinoma: review and update

Adrenocortical carcinoma is a rare endocrine tumor with a poor prognosis. These tumors can be diagnostically challenging, and diagnostic algorithms and criteria continue to be suggested. Myxoid and oncocytic variants are important to recognize to not confuse with other tumors. In addition, the diagnostic criteria are different for oncocytic adrenal carcinomas than conventional carcinomas. Adrenocortical carcinomas usually occur in adults, but can also occur in children. In children these tumors are diagnostically challenging as the histologic features of malignancy seen in an adult tumor may not be associated with aggressive disease in a child. Adrenocortical carcinomas occur with increased frequency in Beckwith-Wiedemann and Li-Fraumeni syndromes, but most occur sporadically. Gene expression profiling by transcriptome analysis can discriminate adrenocortical carcinomas from adenomas and divide carcinomas into prognostic groups. The increasing understanding of the pathogenesis of these tumors may provide increasing treatment targets for this aggressive tumor.

Adrenocortical carcinoma: a comprehensive immunohistochemical study of 40 cases

Adrenocortical carcinomas (ACC) are uncommon tumors of the adrenal cortex that are known to follow an aggressive clinical course. The distinction of these tumors from other neoplasms may sometimes prove difficult due to overlapping clinical, morphologic, and even immunophenotypical features. To this end, we performed a comprehensive immunohistochemical analysis using traditional and novel markers in 40 cases of ACC. An immunohistochemical panel consisting of 10 traditional and novel antibodies was applied to whole tissue sections of ACC including high-molecular weight cytokeratin (HMWCK), low-molecular weight cytokeratin (CAM5.2), inhibin-α, melan A, chromogranin A, synaptophysin, calretinin, steroid receptor coactivator-1 (SRC-1), Pax8, and Ki67. The percentage of positive tumor cells as well as the intensity of staining were evaluated and scored; for Ki67 the percentage of positive tumor cells was recorded. Positive staining was observed for SRC-1 (39/40; 97.5%), inhibin-α (37/40; 92.5%), calretinin (32/40; 80%), synaptophysin (29/40; 72.5%), melan A (26/40; 65%), and CAM5.2 (9/40; 22.5%). Rare cases showed positivity for chromogranin A (2/40; 5%) and Pax8 (1/40; 2.5%). None of the cases showed any reactivity with HMWCK. The Ki67 index ranged from <5% to 20%. We conclude that there is no single specific marker to reliably distinguish ACC from other primary or metastatic neoplasms. However, a combination of immunohistochemical stains in a panel consisting of SRC-1, inhibin-α, calretinin, and HMWCK may be of aid in the differential diagnosis of these tumors. In addition, Pax8 is only rarely positive in ACC, which is a useful tool in their separation from renal neoplasms.

PEComa of the gastrointestinal tract: clinicopathologic study of 35 cases with evaluation of prognostic parameters

Perivascular epithelioid cell tumors (PEComas) are distinctive mesenchymal neoplasms that most often arise in the retroperitoneum, visceral organs, and abdominopelvic sites and usually show reactivity for melanocytic and smooth muscle markers. Fewer than 20 PEComas of the gastrointestinal (GI) tract have been reported, and behavior and criteria for malignancy are incompletely defined. The purpose of this study was to examine the clinicopathologic features of a series of GI PEComas and to evaluate prognostic parameters. A total of 35 PEComas of the GI tract were retrieved from consult and surgical files. Clinical and pathologic features were evaluated, and immunohistochemical analysis was performed. Clinical follow-up information was obtained from medical records and referring physicians. Nineteen patients were female and 16 male (median age 45 y; range, 7 to 70 y). One patient had tuberous sclerosis. Nineteen tumors arose in the colon, 12 in the small bowel, 2 in the stomach, and 1 each in gallbladder and omentum. Median tumor size was 6.2 cm (range, 0.8 to 22 cm). Three tumors were limited to the mucosa and submucosa, 8 extended to the muscularis propria, 15 to the subserosa/serosa, and 8 into the mesentery. The tumors were composed of nests and sheets of usually epithelioid cells with abundant granular eosinophilic to clear cytoplasm, surrounded by a delicate capillary vasculature. Thirteen tumors had mixed epithelioid and spindle cell components, and 2 were purely spindled. Sixteen tumors showed marked nuclear atypia. Seventeen tumors contained occasional pleomorphic cells, and 12 showed diffuse cellular pleomorphism. The median mitotic rate was 2/10 HPF (range, 0 to 36). Vascular invasion was present in 5 cases, and 16 tumors showed necrosis. By immunohistochemistry, 23/35 were positive for HMB45, 23/34 for melan-A, 15/25 for MiTF, 20/35 for smooth muscle actin, 26/35 for desmin, and 3/20 for TFE3. Focal cytoplasmic S100 protein was present in 5/27 cases, 2/25 cases were positive for KIT, and 1 case each was positive for EMA and keratin. Follow-up information was available for 31 patients (median 36 mo; range, 2 to 176 mo). Thirteen patients have developed metastases (10 liver, 3 peritoneum, 4 lymph node, 3 lung, 1 bone, 1 brain, and 1 adrenal). Thus far, 5 patients have died of disease. Metastases were significantly associated with marked atypia, diffuse pleomorphism, and mitoses ≥2/10 HPF. In summary, PEComas of the GI tract occur at similar frequency in female and male patients, most commonly involve the colon, and exhibit variable clinical behavior, ranging from benign lesions to aggressive, high-grade sarcomas. The presence of marked nuclear atypia, diffuse pleomorphism, and mitotic activity are the strongest predictors of malignant behavior.

Evaluation of SF-1 expression in testicular germ cell tumors: a tissue microarray study of 127 cases

Differentiating testicular germ cell tumors from sex-cord stromal tumors can be difficult in certain cases because of overlapping morphologic features and/or an absence of clinically apparent hormonal symptoms. Immunohistochemistry may be needed as an ancillary diagnostic tool in this differential diagnostic setting. Steroidogenic factor-1 (SF-1) is a nuclear transcription factor controlling steroidogenesis and is expressed in developing Sertoli and Leydig cells. Although 1 recent study has reported SF-1 nuclear immunoreactivity in testicular sex-cord stromal tumors, the specificity for this marker in germ cell tumors has not been evaluated. After encountering several problematic cases (including some on testicular biopsy), we sought to determine the diagnostic specificity of SF-1 in a large series of germ cell tumors. Nuclear immunohistochemical expression of SF-1 was evaluated in 127 germ cell tumors using tissue microarray technology with 23 non-germ cell tumor tissues as positive internal controls. No nuclear SF-1 expression was identified in any of the 127 germ cell tumors [including choriocarcinoma (3), embryonal carcinoma (25), epidermal inclusion cyst (1), intratubular germ cell neoplasia unclassified (4), seminoma (72), spermatocytic seminoma (2), teratoma (8), and yolk sac tumor (12)]. All 23 non-germ cell tumor tissues showed strong nuclear SF-1 expression in Sertoli and/or Leydig cells [including testicular atrophy (10), cryptorchidism (2), normal testis (4), hypospermatogenesis (1), immature testis (1), intratubular large cell calcifying Sertoli cell tumor (1), Leydig cell tumor (3), and Sertoli only (1)]. This study documents the absence of SF-1 expression in testicular germ cell tumors and supports its specificity for sex-cord stromal lesions in this diagnostic context.

Mixed corticomedullary adrenal carcinoma

Truly mixed corticomedullary tumors (MCMTs) are extremely rare and present as a single tumor mass composed of an intimately admixed population of both adrenal cortical cells and pheochromocytes. The current study describes the first case of a mixed corticomedullary adrenal carcinoma. In addition, we also review the published data on MCMTs to determine their clinical features, biochemical characteristics, pathological findings, and management. In order to compose this review, a search of the international literature for MCMTs was conducted. Fifteen related articles were found. The clinical and pathological information was obtained for all reported cases. MCMTs were found almost exclusively in females. In the vast majority of patients, the symptoms were related to the tumor's hormone hypersecretion. Hypertension and diabetes were present in 80 and 40 % of cases, respectively. Cushing's syndrome was reported in eight cases (53.33 %). A final diagnosis was made in all cases after surgery based on the pathological results. As of the writing of this article, all published cases of MCMTs had benign clinical behavior, with no instances of metastasis or death due to the tumor. MCMTs are currently considered to be benign tumors. Ours is the first case of malignant MCMT reported in the literature. The potential for malignancy should therefore be considered for these tumors.

Adrenal oncocytic neoplasm: a systematic review

INTRODUCTION

Oncocytic neoplasms as tumors arising in the adrenal glands are rare, usually considered as nonfunctional and benign. In the current literature, there are extremely limited reports of adrenal oncocytic neoplasms; as to date, only 147 cases have been described. The rarity of the event prompted this study which reviews and presents the incidence, histology, diagnosis and therapy of adrenal oncocytic neoplasms.

MATERIALS AND METHODS

A review by systematic literature search was done using the MEDLINE®/Cochrane libraries from 1950 to date using the medical subject headings 'oncocytoma', 'adrenal gland', 'adrenal oncocytoma', 'adrenal oncocytic neoplasm' and 'adrenal oncocytic carcinoma'.

RESULTS

Adrenal oncocytic neoplasm is a rare disease, usually incidentally detected because only 17% are functional adrenal masses. The typical oncocyte displays abundant granular eosinophilic cytoplasm, due to the accumulation of mitochondria. Computed tomography and magnetic resonance imaging are not able to identify or differentiate benign and malignant oncocytic neoplasms. The mainstay of therapy is adrenalectomy, recently performed by laparoscopy. The prognosis is good for benign tumors, while adrenocortical oncocytic carcinoma has a poor survival rate of only 5 years.

CONCLUSIONS

Adrenal oncocytic neoplasm, a rare and mostly benign tumor, usually presents as an incidental, large adrenal mass; surgery is the mainstay of therapy, by means of laparoscopy which is now the most diffuse approach to adrenalectomy.

Ectopic functioning adrenocortical oncocytic adenoma (oncocytoma) with myelolipoma causing virilization

Functioning adrenal adenomas are well-described entities that can rarely occur outside the adrenal gland in the ectopic adrenal tissue. Similarly, myelolipoma is an another benign lesion of the adrenal tissue which can rarely occur outside the adrenal gland. We report the first case of a testosterone producing an extra-adrenal adrenocortical oncocytoma accompanied by a myelolipoma. The patient presented with virilization and elevated androgen levels. Imaging revealed a retroperitoneal mass, which histologically consisted of oncocytes and intermingled myelolipoma. Postoperative androgen levels decreased to normal. The tumor cells were strongly positive for inhibin and Melan-A, supporting the adrenal origin. This case demonstrates a diagnostic challenge in which correlation with histology, immunohistochemistry, and serum endocrine studies led to the final diagnosis.

Immunohistochemical distinction of primary adrenal cortical lesions from metastatic clear cell renal cell carcinoma: a study of 248 cases

The diagnosis of metastatic clear cell renal cell carcinoma (CC-RCC) can be difficult because of its morphologic heterogeneity and the increasing use of small image-guided biopsies that yield scant diagnostic material. This is further complicated by the degree of morphologic and immunophenotypic overlap with nonrenal neoplasms and tissues, such as adrenal cortex. In this study, a detailed immunoprofile of 63 adrenal cortical lesions, which included 54 cortical neoplasms, was compared with 185 metastatic CC-RCCs using traditional [anticalretinin, CD10, antichromogranin, antiepithelial membrane antigen, anti-inhibin, antimelanA, anticytokeratins (AE1/AE3 and AE1/CAM5.2), antirenal cell carcinoma marker, and antisynaptophysin)] and novel [anticarbonic anhydrase-IX, antihepatocyte nuclear factor-1b, antihuman kidney injury molecule-1 (hKIM-1), anti-PAX-2, anti-PAX-8, antisteroidogenic factor-1 (SF-1), and anti-T-cell immunoglobulin mucin-1] antibodies. Tissue microarray methodology was used to simulate small image-guided biopsies. Staining extent and intensity were scored semiquantitatively for each antibody. In comparing different intensity thresholds required for a "positive" result, a value of ≥2+ was identified as optimal for diagnostic sensitivity/specificity. For the distinction of adrenal cortical lesions from metastatic CC-RCCs, immunoreactivity for the adrenal cortical antigens SF-1 (86% adrenal; 0% CC-RCC), calretinin (89% adrenal; 10% CC-RCC), inhibin (86% adrenal; 9% CC-RCC), and melanA (86% adrenal; 10% CC-RCC) and for the renal epithelial antigens hKIM-1 (0% adrenal; 83% CC-RCC), PAX-8 (0% adrenal; 83% CC-RCC), hepatocyte nuclear factor-1b (0% adrenal; 76% CC-RCC), epithelial membrane antigen (0% adrenal; 78% CC-RCC), and carbonic anhydrase-IX (3% adrenal; 87% CC-RCC) had the most potential use. Use of novel renal epithelial markers hKIM-1 (clone AKG7) and/or PAX-8 and the adrenocortical marker SF-1 in an immunohistochemical panel for distinguishing adrenal cortical lesions from metastatic CC-RCC offers improved diagnostic sensitivity and specificity.

Malignant steroidogenic tumor arising from sacrococcygeal mature teratoma

We report a case of malignant steroidogenic tumor arising from a sacrococcygeal teratoma in a 5-year-old girl. A congenital gluteal mass and a 7-month history of precocious puberty had been noted, and a large estrogen-producing tumor in the sacrococcygeal area was found. After a biopsy, chemotherapy and tumor resection were performed, and no recurrence has been observed. The biopsy specimen showed small clusters of atypical round cells adjacent to a mature teratoma. They had large round nuclei with prominent nucleoli and abundant eosinophilic cytoplasms and were positive for vimentin, steroidogenic factor-1, inhibin α, and melan-A. Increased mitoses, vascular invasion, and necrosis were noted. The tumor was diagnosed as sacrococcygeal mature teratoma, with malignant steroidogenic tumor as somatic malignant transformation. Although several kinds of somatic malignant transformation of sacrococcygeal teratoma have been reported, to the best of our knowledge, this is the first case of malignant steroidogenic tumor arising from sacrococcygeal teratoma.

Sporadic hemangioblastoma of the kidney: an underrecognized pseudomalignant tumor?

Hemangioblastoma is a benign tumor that can occur sporadically, or in association with von Hippel-Lindau disease in approximately one-quarter of the cases. Only exceptionally does it occur outside the central nervous system. This report describes 2 cases of sporadic renal hemangioblastoma, with 1 patient presenting with hematuria and polycythemia, and the other low back pain. Histologically, the tumors were circumscribed, and composed of sheets of large polygonal cells traversed by arborizing thin-walled blood vessels. Many of the tumor cells showed pleomorphic nuclei, but the mitotic figures were rare. The cytoplasm was eosinophilic, and occasionally finely vacuolated indicating the presence of lipid. The diagnosis of hemangioblastoma was confirmed by negative immunostaining for cytokeratin, and positive staining for α-inhibin, S100, and neuron-specific enolase. This benign neoplasm which can be mistaken for various malignancies such as renal cell carcinoma, epithelioid angiomyolipoma, adrenal cortical carcinoma, and paraganglioma, deserves wider recognition for its occurrence as a primary renal tumor.

The use of immunohistochemistry in the diagnosis of metastatic clear cell renal cell carcinoma: a review of PAX-8, PAX-2, hKIM-1, RCCma, and CD10

The diagnosis of metastatic clear cell renal cell carcinoma may be difficult in some cases, particularly in the small image-guided biopsies that are becoming more common. As targeted therapies for renal cell carcinoma are now standard treatment, the recognition and diagnosis of renal cell carcinoma has become even more critical. Many adjunctive immunohistochemical markers of renal epithelial lineage such as CD10 and RCCma have been proposed as aids in the diagnosis of metastatic renal cell carcinoma, but low specificities often limit their utility. More recently described markers (PAX-2, PAX-8, human kidney injury molecule-1, hepatocyte nuclear factor-1-β, and carbonic anhydrase-IX) offer the potential for greater sensitivity and specificity in this diagnostic setting; however, knowledge of their expected staining in other neoplasms and tissues is critical for appropriate use. In this review, we discuss the most widely used immunohistochemical markers of renal lineage with an emphasis on their sensitivity and specificity for metastatic clear cell renal cell carcinoma. Subsequently, we present a variety of organ-specific differential diagnostic scenarios in which metastatic clear cell renal cell carcinoma might be considered and we propose immunopanels for use in each situation.