Immunohistochemical evidence for mesothelial origin of paratesticular adenomatoid tumour

Extratesticular masses focusing on MRI findings

Scrotal masses, whether cystic or solid lesions, are routinely evaluated using ultrasonography. Magnetic resonance imaging (MRI) may be used for further investigation in cases with atypical findings, difficult diagnoses, large masses, and/or unclear relationships with the surrounding tissues. Scrotal solid masses are divided into intra- and extra-testicular masses. A staggering 90% of the intratesticular masses are malignant, whereas 75% of extratesticular masses are benign. Extratesticular masses are less common than intratesticular masses; however, some extratesticular masses present characteristic MRI findings. Familiarity with these specific MRI features of extratesticular masses is beneficial to radiologists, as appropriate diagnoses can help avoid unnecessary invasive treatments such as orchiectomy. In this review, we describe fibrous pseudotumors, polyorchidism, adenomatoid tumors, and scrotal leiomyoma as benign paratesticular masses, focusing on their characteristic imaging features on MRI. Although these tumors are extremely rare, their MRI findings are distinctive, and accurate diagnoses can prevent unnecessary orchiectomy. In addition, to demonstrate the pitfalls of diagnosing extratesticular masses, we present a case of seminoma misidentified as extratesticular masses due to large extensions outside the testis. Spermatic cord sarcoma, including rhabdomyosarcoma, leiomyosarcoma, and liposarcoma, and metastasis to the spermatic cord are described as malignant extratesticular masses. This review focused on extratesticular masses and elaborates the imaging findings that can aid in the accurate diagnosis using MRI.

Testicular/paratesticular mesothelial tumours: Uncommon histopathologic entities in a very complex anatomical site

Mesothelial tumours of the testicular/paratesticular region are uncommon, poorly characterised and difficult-to-diagnose lesions. They encompass entirely benign proliferations (adenomatoid tumour) and malignant, very aggressive tumours (mesothelioma) whose morphological features can be overlapping, highly variable and confounding. Moreover, testicular/paratesticular mesothelial tumours comprise relatively new entities with indolent behaviour (well-differentiated papillary mesothelial tumour) as well as tumours which cannot be correctly included in any of the aforementioned categories and whose classification is still controversial. The molecular profile of such tumours represents an open issue. In fact, despite the recent discoveries about the genomic landscape of mesothelial proliferations at other sites (pleura, peritoneum), testicular/paratesticular mesothelial tumours, and namely mesotheliomas, are too rare to be extensively studied on large case series and they could arguably hide relevant differences in their molecular background when compared to the more common pleural/peritoneal counterparts.The aim of this review is to provide a guide for the pathological assessment of testicular/paratesticular mesothelial tumours. Herein, we describe the most recent updates on this topic according to the latest (year 2022) World Health Organisation Classification of Urinary and Male Genital Tumours (5th edition) and current literature. The diagnostic criteria, the main differentials and the role of ancillary techniques in the diagnosis of mesothelial testicular/paratesticular tumours are discussed.

Adenomatoid Tumor of Epididymis Associated with Tubular Ectasia of Rete Testis: Sonographic Evaluation

Paratesticular tumors are a relatively rare group of mesenchymal tumors, accounting for 7%-10% of all intrascrotal tumors. Adenomatoid tumor of the epididymis is the most common epididymal tumor. It is difficult to distinguish intra- versus paratesticular tumors and to know the nature of the lesion (benign versus malignant) on clinical examination since they may have similar presentation; therefore, ultrasound examination of these lesions is required to demonstrate its extratesticular location and also to suggest its benign nature. Elastography can further help in characterizing the lesion by evaluating the stiffness of the tumor. Here, we present a case of adenomatoid tumor of the left epididymis with tubular ectasia of the rete testis.

Adenomatoid tumours of the gastrointestinal tract - a case-series and review of the literature

AIMS

Adenomatoid tumours are mesothelial-derived benign neoplasms with a predilection for the genital tract. Extragenital sites are rare and can cause significant diagnostic challenges. Herein, we describe the clinicopathological features of a cohort of adenomatoid tumours involving the gastrointestinal tract and liver in order to more clearly characterise their histological findings and aid in diagnosis.

METHODS AND RESULTS

The pathology databases at four institutions were searched for adenomatoid tumours involving the gastrointestinal tract or liver, yielding eight cases. Available clinicoradiological and follow-up data were collected from the medical records. Six tumours were incidentally discovered during imaging studies or at the time of surgical exploration for unrelated conditions; presenting symptoms were unknown in two patients. Histologically, the tumours were well-circumscribed, although focal ill-defined borders were present in four cases. No infiltration of adjacent structures was identified. Architectural heterogeneity was noted in five (63%) tumours; an adenoid pattern often predominated. The neoplastic cells were flattened to cuboidal with eosinophilic cytoplasm. Cytoplasmic vacuoles mimicking signet ring-like cells were present in five (63%) cases. Three (38%) cases showed involvement of the mesothelium with reactive mesothelial hyperplasia. Cytological atypia or increased mitotic activity was not identified. The surrounding stroma ranged from oedematous/myxoid to densely hyalinised. Immunohistochemistry confirmed mesothelial origin in all cases evaluated. No patients developed recurrence of disease.

CONCLUSIONS

The current study evaluates the clinicopathological findings in a collective series of gastrointestinal and hepatic adenomatoid tumours, correlating with those described in individually reported cases. We highlight common histological features and emphasise variable findings that could mimic a malignant neoplasm.

Metastatic Seminoma with Positive Staining of Cytokeratin and MOC31: A Diagnostic Pitfall

Retroperitoneal metastasis of seminoma often occurs in the higher stage through lymph nodes. Generally, seminoma expresses specific germ cell markers while being negative for carcinoma markers. We present a unique case of cytokeratin positive seminoma initially presented as retroperitoneal metastasis. The diagnosis was made based on the histological features and immunohistochemical stains. Testicular ultrasound confirmed the primary tumor in the patient's left testicle. Pathologists should always be aware of germ cell tumors when encountering a metastasis of an unknown primary.

Adenomatoid Tumor: A Review of Pathology With Focus on Unusual Presentations and Sites, Histogenesis, Differential Diagnosis, and Molecular and Clinical Aspects With a Historic Overview of Its Description

Adenomatoid tumors have been described almost a century ago, and their nature has been the subject of debate for decades. They are tumors of mesothelial origin usually involving the uterus, the Fallopian tubes, and the paratesticular region. Adenomatoid tumors of the adrenal gland, the liver, the extragenital peritoneum, the pleura, and the mediastinum have been rarely reported. They are usually small incidental findings, but large, multicystic and papillary tumors, as well as multiple tumors have been described. Their pathogenesis is related to immunosuppression and to TRAF7 mutations. Despite being benign tumors, there are several macroscopic or clinical aspects that could raise diagnostic difficulties. The aim of this review was to describe the microscopic and macroscopic aspects of adenomatoid tumor with a special focus on its differential diagnosis and pathogenesis and the possible link of adenomatoid tumor with other mesothelial lesions, such as the well-differentiated papillary mesothelioma and the benign multicystic mesothelioma, also known as multilocular peritoneal cysts.

Images - Adenomatoid tumor of testis, concerning for malignancy after ultrasound

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Adenomatoid tumor of the testis mimicking malignant testicular cancer on multiparametric ultrasound

BACKGROUND

Adenomatoid tumor is one of the most common histological subtypes of paratesticular cancer arising from the epididymis. In very rare cases, these tumors appear as intratesticular lesions originating in the tunica albuginea, representing a diagnostic challenge.

CASE PRESENTATION

We present a case of a 51-year-old man with a small (0.9 cm) hyperechoic lesion of the left testicle mimicking testicular cancer on multiparametric ultrasound. The lesion was localized in the peripheral zone, confirming vascularization and increased stiffness on contrast-enhanced ultrasound and real-time elastography. Preoperative tumor markers and hormone levels were within normal ranges. Staging computed tomography was negative. Organ-sparing surgery with tumor enucleation and frozen section analysis was performed, confirming testicular adenomatoid tumor.

CONCLUSION

Currently, no typical ultrasound features can definitively distinguish intratesticular adenomatoid tumors from malignant testicular masses. Thus, a surgical approach is almost always considered in such a case for both diagnostic and therapeutic purposes.

Updates in Benign Lesions of the Genitourinary Tract

The genitourinary tract is a common site for new cancer diagnosis, particularly for men. Therefore, cancer-containing specimens are very common in surgical pathology practice. However, many benign neoplasms and nonneoplastic, reactive, and inflammatory processes in the genitourinary tract may mimic or cause differential diagnostic challenges with malignancies. Emerging clinicopathologic, immunohistochemical, and molecular characteristics have shed light on the pathogenesis and differential diagnosis of these lesions. This review addresses differential diagnostic challenges related to benign genitourinary tract lesions in the kidney, urinary bladder, prostate, and testis, with emphasis on recent advances in knowledge and areas most common in diagnostic practice.

Adenomatoid Tumor of the Tunica Albuginea in a Boy: A Case Report and Literature Review

Adenomatoid tumors (AT) are the most common paratesticular neoplasms and account for approximately 30% of all paratesticular masses. Most of them occur in the third or fourth decade and present as well-defined firm and painless masses. We report here a case of adenomatoid tumor from tunica albuginea. This patient is a 12-year-old boy with left testicular pain for 6 months. Scrotal ultrasonography revealed a solid mass of paratesticular origin. The histology and immunohistochemistry confirmed the final diagnosis. A right tumor resection was performed. Because of its rarity, the clinical and histopathologic appearance is seldom illustrated. Here we present a case report and a comprehensive literature review with the objective of providing useful information on this entity.

The Utility of Immunohistochemistry in the Differential Diagnosis of Gynecologic Disorders

Context

Immunohistochemistry has assumed an increasing role in the identification and characterization of gynecologic disorders including lesions with deceptively bland morphology, uncommon and underdiagnosed neoplasms, and neoplasms with specific genetic alterations associated with overexpression or loss of expression of specific proteins. The diagnostic accuracy has been significantly improved owing to the discovery and increasing experience with the tumor-associated biomarkers, and the increasing demand for precise tumor classification to assess suitability for the expanding therapeutic modalities including clinical trials.

Objective

To differentiate lesions of the gynecologic tract through the use of effective immunohistochemical panels.

Data Sources

Literature review and authors' personal practice experience.

Conclusions

The application of diagnostic and prognostic immunohistochemical panels has enabled pathologists to better guide therapeutic decisions and to better predict the clinical outcome. It is now well established that the use of ancillary testing, including immunohistochemistry, has a significant power in the identification, differentiation, and classification of reactive, premalignant, and malignant gynecologic disorders. This article discusses the utilities and pitfalls of the commonly used immunohistochemical markers in the context of overlapping morphologic features encountered in the uterus, ovaries, and fallopian tubes.

The Application of Immunohistochemical Biomarkers in Urologic Surgical Pathology

Context

Tumors of the genitourinary tract can be diagnostically challenging, particularly in core biopsies and cystoscopic biopsies with limited material. Immunohistochemistry is a valuable tool to use when morphology alone is insufficient for diagnosis.

Objectives

To review tumors and benign lesions of the kidney, urinary bladder, prostate gland, testis, and paratesticular structures with an emphasis on difficult differential diagnoses, as well as staining patterns in normal tissue. Recommended immunohistochemical stain panels are discussed that can assist in the diagnostic workup.

Data Sources

Review of current literature.

Conclusions

Immunohistochemistry is a valuable tool, assisting in the diagnosis of problematic tumors and benign lesions of the genitourinary tract.

Adenomatoid tumor of the testis in a child

Adenomatoid tumors are rare benign neoplasms thought to be of mesothelial origin. Although most reported cases arise from the epididymis, rare cases have been reported in the spermatic cord, testicular tunica, ejaculatory ducts, prostate, and suprarenal recess. We describe a 4.5-year-old boy who presented with a relatively asymptomatic right testicular mass that was resected and confirmed to be adenomatoid tumor of the testis by histopathology. Because of its rarity, the clinical and histopathologic aspects are discussed.

Adenomatoid tumour of testis

Adenomatoid tumour is a rare neoplasm of mesothelial origin commonly seen in male and female genital tract. In this case report, the authors present a case of adenomatoid tumour in a 35-year-old male who presented with 1-year history of scrotal swelling. A clinical diagnosis of testicular neoplasm was made but final diagnosis of adenomatoid tumour was made after excisional biopsy.

Adenomatoid tumor of testis

Adenomatoid tumors are responsible for 30% of all paratesticular masses. These are usually asymptomatic, slow growing masses. They are benign tumors comprising of cords and tubules of cuboidal to columnar cells with vacuolated cytoplasm and fibrous stroma. They are considered to be of mesothelial origin supported by histochemical studies and genetic analysis of Wilms tumor 1 gene expression. Excision biopsy is both diagnostic and therapeutic procedure. The main clinical consideration is accurate diagnosis preventing unnecessary orchiectomy. Diagnostic studies include serum tumor markers (negative alpha fetoprotein, beta HCG, LDH) ultrasonography (hypoechoic and homogenous appearance) and frozen section.

Adenomatoid tumors of the female and male genital tracts: a clinicopathological and immunohistochemical study of 44 cases

Adenomatoid tumors of the female and male genital tracts are well characterized as mesothelial in origin, but a detailed histological and immunohistochemical analysis comparing both traditional and newer mesothelial markers across gender and site has not been formally conducted. A variety of morphologic features previously described as characteristic of adenomatoid tumors were evaluated in 44 adenomatoid tumors from the male and female genital tracts. Immunohistochemical analysis with pankeratin (AE1/CAM5.2), WT-1, calretinin, CK5/6, D2-40, and caldesmon was also performed. The extent and intensity of staining were scored semiquantitatively on one representative section per case and mean value for each parameter was calculated. All (n=44) the adenomatoid tumors from both the female and male genital tracts demonstrated a distinctive thread-like bridging strand pattern. Lymphoid aggregates were seen in all 12 adenomatoid tumors of male patients, but in only 4 of 32 (13%) tumors in female patients (P<0.0001). The remaining morphologic features were variably present with no clear sex predilection. Pankeratin, calretinin, and D2-40 reactivity were identified in all female (n=32) and male (n=12) genital tract adenomatoid tumors. Adenomatoid tumors expressed WT-1 in 11/12 (92%) male patients and in 31/32 (97%) female patients. In male patients, reactivity for CK5/6 and caldesmon was found in 1/12 (8%) and 0/12 (0%) adenomatoid tumors (respectively), whereas reactivity in female patients was found in 5/32 (16%) and 1/32 (3%); respectively. Female tumors differ from their male counterparts by the frequent absence of lymphoid aggregates and the presence of a circumscribed margin when occurring in the fallopian tube. Of the putative mesothelial markers evaluated, calretinin, D2-40, and WT-1 show a similar immunoprofile and have a higher sensitivity than CK5/6 and caldesmon in genital tract adenomatoid tumors. However, the presence of additional, often strong expression of WT-1 in normal tissues of the female genital tract limits the utility of WT-1 in this setting.

Benign and Malignant Neoplasms of the Testis and Paratesticular Tissue

Benign and malignant tumors of the testes and paratesticular tissues present an interesting spectrum of diagnostic entities often encountered in routine surgical pathology practice. Germ cell tumors are the most common tumors of the testes and, despite a rising incidence, have excellent prognosis because of their radiosensitivity and/or effective chemotherapeutic agents. The proper classification of these tumors aids in the choice of appropriate treatment options. This article reviews benign and malignant neoplastic entities of the testes and paratesticular tissues and illustrates the classic pathologic characteristics. The differential diagnosis, along with ancillary studies, clinical significance, and presentation are discussed also.

Neoplastic and nonneoplastic conditions of serosal membrane origin: CT findings

Computed tomography (CT) is an important imaging modality for diagnosis and follow-up of neoplastic or nonneoplastic conditions of the serosal membrane. The characteristic CT findings of malignant pleural mesothelioma include unilateral pleural effusion, thickening of the mediastinal pleura, and circumferential and nodular pleural thickening of greater than 1 cm. Malignant peritoneal mesothelioma manifests as a large mass or diffuse peritoneal thickening without a definable mass and is difficult to differentiate from peritoneal carcinomatosis or tuberculosis. The imaging features of primary serous papillary carcinoma of the peritoneum resemble those of peritoneal carcinomatosis; however, the ovary is usually of normal size. The possibility of desmoplastic small round cell tumor should be considered in children or young adults with multiple peritoneal masses and no identifiable primary malignancy. The CT findings of secondary tumors include a variable amount of fluid in the serosal cavity, thickening of the serosal lining (irregular and nodular), and serosal implants. Nonneoplastic conditions manifest as focal or diffuse thickening of the serosal membrane, a variable amount of fluid in the serosal cavity, and a soft-tissue mass at CT. Although the CT findings of some of the conditions overlap, knowledge of the typical findings is helpful in narrowing the differential diagnosis.

Evidence-based Guidelines for the Utilization of Immunostains in Diagnostic Pathology: Pulmonary Adenocarcinoma Versus Mesothelioma

There are no firmly established guidelines for the use of antibodies in immunohistology as individual tests or panels. Practicing pathologists must rely on information available in individual publications, review articles, books, and internet-based databases to develop diagnostic immunohistochemical algorithms for their individual practices. In contrast, other medical specialties have crafted many evidence-based practice guidelines (EBG) that are widely used; these have helped to augment standardization and cost effectiveness. In particular, the use of several "epithelial" and "mesothelial" antibodies has been proposed to distinguish epithelioid malignant mesothelioma from metastatic pulmonary adenocarcinoma. Other authors have previously done systematic literature reviews of this subject up through 2004 and integrated the results of 88 publications into summarized test-performance values for 15 preselected immunohistochemical markers. The results suggested that 7 tests provide optimal sensitivity and specificity (MOC-31, BG8, CEA, TTF-1, CK5/6, WT-1, and HBME-1), but they provide no guidance for integration of such data into EBG. Odds ratios (ORs) were employed to compare the effectiveness of any single test, and chosen combinations thereof, in the differential diagnosis of malignant mesothelioma and metastatic pulmonary adenocarcinoma. Surprisingly, selected single immunostains or antibody pairs yielded ORs (varying from 96.34 to 1233.19) that were equal or better in efficacy when compared with more comprehensive panels. These results support the potential value of systematic reviews, meta-analysis, and OR calculations for development of EBG in diagnostic immunohistology.

Morphological approach to tumours of the testis and paratestis

Most neoplastic scrotal masses ultimately prove to be germ cell tumours and are recognisable with routine haematoxylin and eosin-stained sections. The differential diagnosis may be focused, even before reviewing histological sections, by knowledge of patient age, medical history, tumour site (testicular vs paratesticular) and gross findings. Some cases may prove to be diagnostically challenging, including rare tumours, a common tumour with an unusual pattern, a metastatic tumour, or a neoplasm with features that mimic another tumour. Several morphological patterns are seen with some frequency and these generate recurring sets of differential diagnostic considerations. These common patterns include testicular tumours with a predominant diffuse arrangement of cells with pale to clear cytoplasm, tumours with a glandular/tubular pattern, tumours with a microcystic pattern and tumours composed of oxyphilic cells. Intratubular proliferations of atypical cells, paratesticular glandular and/or papillary tumours, or tumours with spindle cell morphology can also be challenging to diagnose correctly. In some problematic cases, immunohistochemical staining may be useful to resolve these differential diagnoses.

Adenomatoidtumor des Hodens – eine seltene Entität

Adenomatoid tumor with intra-testicular localization is rare. Although most reported cases arise from the epididymis, rare cases have been reported in the testicular tunica, spermatic cord, ejaculatory ducts, prostate and suprarenal recess. Adenomatoid tumors occur in both sexes and are also found in the uterus, ovary and fallopian tubes of the female genital tract. Adenomatoid tumors are benign proliferations of mesothelial origin. We report the case of a 50-year-old male with an adenomatoid tumor of the left testis. Because of its rarity, the clinical, diagnostic and therapeutic aspects as well as the possibilities of testicular preservation are discussed.

The use of immunohistochemistry in the differential diagnosis of tumors of the testis and paratestis

Although most testicular and paratesticular tumors can be recognized by their light microscopic features, some raise significant differential diagnostic questions. Immunohistochemical staining has proved of significant value in this situation. There is still a role for the traditional markers, including placental-like alkaline phosphatase and alpha-fetoprotein, but newer markers provide additional support and often have greater sensitivity and specificity for many diagnoses. OCT4 is virtually 100% sensitive and specific for seminoma, embryonal carcinoma, and intratubular germ cell neoplasia, unclassified type. Inhibin-alpha, among testicular tumors, is limited to those in the sex cord-stromal category or those having adrenocortical-type differentiation (testicular tumor of the adrenogenital syndrome) or of trophoblastic lineage. Calretinin is another positive marker for the sex cord-stromal tumors but has less specificity. Additional markers, including differential cytokeratins, c-kit, CD30, epithelial membrane antigen, S-100, melan-A, and others, are useful in specific situations. This article reviews the application of immunohistochemical markers for a number of differential diagnostic considerations in the testis and paratestis categorized according to their light microscopic patterns.

Adenomatoid tumor of the tunica albuginea

Adenomatoid tumors are benign mesothelial tumors most commonly found in the paratesticular structures, especially the epididymis. Herein, we report a case of adenomatoid tumor originating in the tunica albuginea and mimicking an intratesticular neoplasm. We review the ultrasonographic presentation and literature regarding adenomatoid tumors originating in the tunica albuginea and testicular parenchyma.

Adenomatoid tumor of the testes

Adenomatoid tumors are rare benign neoplasms thought to be of mesothelial origin. Although most reported cases arise from the epididymis, rare cases have been reported in the spermatic cord, testicular tunica, ejaculatory ducts, prostate, and suprarenal recess. In female subjects, adenomatoid tumors are commonly found in the uterus and fallopian tubes. Because of the benign nature of this tumor, the treatment of choice is local excision. We describe a rare case of adenomatoid tumor of the testis treated by local excision.

Adenomatoid Tumors of the Female and Male Genital Tracts Express WT1

Adenomatoid tumors are benign proliferations most often encountered in the female and male genital tracts. The mesothelial phenotype of these unusual tumors has been established by a variety of ultrastructural and immunohistochemical studies, although their etiology is by no means certain. The expression of the Wilms' tumor suppressor gene, WT1, in normal, hyperplastic, and malignant mesothelial cells prompted us to analyze the expression pattern of WT1 in a series of 24 adenomatoid tumors occurring in the uterus, fallopian tube, ovary, epididymis, scrotum, and testis. Twenty-three of the tumors expressed WT1 protein and the same number expressed calretinin, another marker of mesothelial differentiation. The one tumor that failed to stain with calretinin was positive for WT1. These results provide further support for mesothelial differentiation of adenomatoid tumors and suggest that the presence of WT1 expression may be useful in the differential diagnosis of these uncommon neoplasms, especially when they present in unusual settings or expression of other mesothelial markers is absent.

Paratesticular mesothelial proliferations

Varied mesothelial proliferations are found around the testes. Benign reactive mesothelial proliferations in hydrocoeles may be very florid and histologically worrisome, but these can usually be separated from malignant mesotheliomas of the tunica vaginalis because they are confined to a sharply demarcated zone near the luminal surface. In addition, benign inflamed hydrocoeles tend to show a distinct zonation with cellular areas near the luminal surface and more fibrotic areas beneath. The proliferating mesothelial cells in benign reactions often form lines that are parallel to the surface of the hydrocoele. Malignant mesotheliomas of the tunica vaginalis are usually grossly visible as single or multiple nodules. Histologically, they show an epithelial- or mixed epithelial- and sarcomatous-morphologic image, with evidence of stromal invasion. Well-differentiated papillary mesotheliomas are usually solitary exophytic nodules with a distinctive morphologic appearance and benign course, but they must be carefully separated from malignant mesotheliomas with a focally exophytic papillary growth pattern. By definition, well-differentiated papillary mesotheliomas do not exhibit stromal invasion. Peritesticular adenomatoid tumors are also very common; they are benign circumscribed cellular nodules with an appearance comparable to that of adenomatoid tumors in other body locations such as the uterine serosa.

Adenomatoid tumor of the adrenal gland with micronodular adrenal cortical hyperplasia

We report a case of an adenomatoid tumor (AT) of an adrenal gland with micronodular adrenal cortical hyperplasia (ACH). A 51-year-old man was found to have newly developed hypertension with clinical evidence of primary aldosteronism. A computerized tomogram of the abdomen revealed a solitary mass in the right adrenal gland. He underwent a right adrenalectomy for a presumptive clinical diagnosis of a solitary aldosterone-producing adrenal cortical adenoma. On histopathologic examination, the adrenal gland demonstrated an AT, diagnosed by the characteristic histological features, immunohistochemical stain results, and electron microscopic findings. The surrounding adrenal cortex showed multiple small hyperplastic cortical nodules. After the adrenalectomy, the patient's blood pressure normalized. Primary AT of the adrenal gland coexisting with micronodular ACH associated with hypertension has not been previously reported.

Adenomatoid tumor of the adrenal gland: a clinicopathologic study of five cases and review of the literature

We report the clinicopathologic, immunophenotypic, DNA ploidy, and MIB-1 proliferative findings of five adenomatoid tumors of the adrenal gland. All patients were male, and tumors were incidental radiologic, surgical, or autopsy findings. Mean patient age at diagnosis was 41 years (range 31-64 years). The tumors ranged from 1.2 to 3.5 cm (mean 2.8 cm; median 3.2 cm) in greatest dimension, and all originated within the adrenal gland. The tumors were composed of anastomosing variably sized tubules lined by epithelioid as well as flattened cells. Signet-ring-like cells were present in all cases. The previously described histologic patterns of adenomatoid tumor, adenoid, angiomatoid, cystic, and solid, were observed, and each tumor contained multiple histologic patterns. In three of five cases, there was extra-adrenal extension of tumor into periadrenal adipose tissue. All adenomatoid tumors infiltrated the adrenal cortex, and in four cases the adrenal medulla was involved. All tumors exhibited strong immunoreactivity for calretinin, cytokeratins AE1/AE3, and CAM 5.2, cytokeratin 7, and vimentin. Tumors showed weak and focal immunoreactivity for cytokeratin 5/cytokeratin 6 and were negative for CD15, CD31, CD34, cytokeratin 20, MOC31, and polyclonal carcinoembryonic antigen. Ploidy analysis using Feulgen-stained sections and image analysis showed that three tumors were diploid and two were tetraploid. Tumors exhibited low MIB-1 proliferative activity, ranging from 0.2% to 2.7% (mean 1.6%). In three cases with clinical follow-up, no recurrence or metastases occurred. Adrenal gland adenomatoid tumors are morphologically and immunophenotypically identical to adenomatoid tumors of the genital tract and appear benign.

Adenomatoid tumor of the pancreas: a case report with comparison of histology and aspiration cytology

We present a 58-year-old woman who presented with a 1.5-cm, hypodense lesion in the head of the pancreas. Endoscopic ultrasound-guided fine-needle aspiration yielded bland, monotonous cells with wispy cytoplasm, slightly granular chromatin, and small nucleoli. A presumptive diagnosis of a neuroendocrine lesion was rendered. Whipple procedure yielded a well-circumscribed, encapsulated lesion with dense, hyalinized stroma and a peripheral rim of lymphocytes. Spindled and epithelioid cells formed short tubules, cords, and nests. The neoplasm stained for CK 5/6, calretinin, vimentin, CD 99, pancytokeratin, and EMA, consistent with mesothelial origin. This characteristic histology and immunohistochemistry is consistent with an adenomatoid tumor. We believe we are the first to report this benign neoplasm in such an unusual location. Herein we address the diagnosis of adenomatoid tumor by histology, immunohistochemistry, and aspiration cytology. Our case is particularly unique in that the histology and cytology are compared and correlated.

Mediastinal epithelioid solitary fibrous tumor

We describe the case of a 74-year-old man with a mediastinal tumor composed predominantly of epithelioid cells exhibiting histopathologic and immunohistochemical features intermediate between those of a solitary fibrous tumor and those of a cellular adenomatoid tumor. We discuss the differential diagnosis and possible histogenesis of this unusual neoplasm, and we propose the term epithelioid solitary fibrous tumor for this entity.

Extragenital adenomatoid tumor of a mediastinal lymph node

Adenomatoid tumors are benign neoplasms found predominantly in male and female genital tracts. Rare extragenital adenomatoid tumors have been discovered that involve serosal surfaces and nonmesothelial-lined organs such as adrenal glands. Since the discovery of adenomatoid tumors, their histogenetic origin has been debated. Many researchers support a mesothelial cell origin for adenomatoid tumors because these tumors characteristically express a mesothelial phenotype. Tumor derivation from primitive pluripotent mesenchymal cells and coelomic epithelium also has been suggested because of the anatomical distribution of the tumors. Despite their characteristic mesothelial phenotype and histological appearance, adenomatoid tumors have an extensive differential diagnosis that includes vascular neoplasms, malignant mesothelioma, germ cell tumors, and metastatic adenocarcinoma. Recognition of these tumors may be especially difficult when examined at frozen section and when adenomatoid tumors are encountered in rare extragenital sites. We describe an adenomatoid tumor of a mediastinal lymph node that was found incidentally during a redo Collis-Nissen gastroplasty. On frozen section examination, this tumor was misinterpreted as metastatic adenocarcinoma. The hematoxylin-eosin histological, immunohistochemical, and ultrastructural studies confirmed the mesothelial phenotype of this tumor. To our knowledge, this is the first description of a lymph node adenomatoid tumor.

Localized malignant mesothelioma of the epithelial type occurring as a primary hepatic neoplasm: a case report with review of the literature

We report a localized malignant mesothelioma of the epithelial type, occurring as a primary hepatic neoplasm in a 64-year-old male. He was found to have a mass located in the right lobe of the liver. Surgery was carried out with resection of the mass from the right hepatic lobe, with partial resection of the diaphragm. Grossly, an ill-defined tumor was present in the hepatic parenchyma. Histologically, the tumor displayed a predominant tubular pattern of growth with a desmoplastic stroma. The tubules were lined by a single layer of cuboidal or flattened cells with pleomorphic vesicular nuclei. A hyaluronidase-digestible, mucin-like substance was demonstrated in the lumen and tumor cytoplasm. The tumor cells were immunohistochemically positive for calretinin, HBME-1, cytokeratin, i.e. AE1/AE3 and CAM 5.2, but negative for carcinoembryonic antigen, CD 34 and Leu M1. Moreover, the tumor cells showed nuclear accumulation of the p53 oncopotein and reacted frequently with Ki-67 antibody. These findings support the concept that malignant mesothelioma of the epithelial type may occur at extrapleural sites. To the best of our knowledge, this is the first reported case of localized malignant primary mesothelioma arising in the liver.

Adenomatoid tumors of testis and epididymis: a report of two cases

Adenomatoid tumors are rare benign tumors of female and male genital tracts. In this paper, we reported an epididymal and a testicular adenomatoid tumor in two patients presented with enlarged intrascrotal mass.

Ovarian mixed-epithelial carcinomas with a microcystic pattern and signet-ring cells

Primary ovarian carcinomas with unusual histologic patterns can be difficult to differentiate from metastases. In this study, we reviewed 15 cases of mixed-epithelial carcinoma (12 serous, 1 serous and endometrioid, 1 endometrioid, 1 undifferentiated) with a predominant microcystic pattern and signet-ring cells. The patients' ages ranged from 31 to 78 (mean 58) years. The microcystic component in 11 patients had features of high-grade carcinoma and in 4 patients had features of low-grade carcinoma associated with areas of borderline tumor. The tumors in all 15 patients showed a predominant microcystic growth pattern composed of small cysts that were variable in size and shape. Signet-ring cells were also present in all cases (diffusely in nine cases, focally in six cases) within the neoplastic epithelial proliferation. Mucin was present in the lumina of some of the microcysts and in the cytoplasm of most of the signet-ring cells. A microcystic pattern and mucin-containing signet-ring cells can be seen as small foci or as a predominant component in primary epithelial nonmucinous ovarian carcinomas. It is important for pathologists to recognize these unusual findings in ovarian neoplasms, because they may produce a confusing apperance, even potentially suggesting a metastasis.