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

The Incidental Diagnosis of Adenomatoid Tumour on Fallopian Tubes Submitted for Tubal Ligation at a Tertiary Laboratory in Northern Pretoria, South Africa

Introduction

Adenomatoid tumours are the most common benign mesothelial neoplasms of the fallopian tube. They are usually diagnosed incidentally in specimens submitted for bilateral tubal ligation and can be mistake for vascular or epithelial lesions.

Materials and methods

A retrospective analysis of cases with adenomatoid tumour of the fallopian submitted for tubal ligation from 2012 to 2020. The clinicopathological characteristic data was retrieved from the laboratory information system.

Results

A total of 11 cases with adenomatoid tumour of the fallopian tubes submitted for tubal ligation were identified in women with average age of 30.9 years. In all the cases, only 1 fallopian tube was affected. Grossly, the fallopian tubes did not show any discernible tumour. Immunohistochemical stains confirmed the diagnosis of adenomatoid tumours in all the cases.

Conclusion

Adenomatoid tumours in fallopian tubes are infrequent, and pathologists shouldn't overlook them especially in unsuspicious instances. As frequent as adenomatoid tumour of the fallopian tubes are uncommon, pathologists show be aware of as their misdiagnosis could lead mismanagement of patient with far reaching complication.

Primary adenomatoid tumor of the adrenal gland: A case report and literature review

RATIONALE

Adenomatoid tumors are rare benign tumors, mainly involving the reproductive tract, such as the epididymis in men and the uterus and fallopian tubes in women. However, a few cases can occur outside the reproductive tract. Herein, we report a rare case of a primary adenomatoid tumor of the adrenal gland.

PATIENT CONCERNS

A 50-year-old man underwent ultrasound examination and was found to have a right adrenal mass without elevated blood pressure, weakness after fatigue, frequent nocturnal urination urgency, pain, or a history of hematuria. The patient's general health was normal. Computed tomography revealed a polycystic mixed-density lesion in the right adrenal region, approximately 7.3 × 4.5 cm in size.

DIAGNOSES

Based on the clinical information, morphological features, and immunohistochemistry results, a pathological diagnosis of primary adenomatoid tumor of the adrenal gland was made.

INTERVENTION

Excision of the right adrenal gland and tumor through the 11 ribs.

OUTCOMES

The patient's postoperative course was uneventful.

LESSONS

Preventing misdiagnosis adenomatoid tumors with other types of adrenal gland tumors or metastatic tumors is imperative. Morphological and immunohistochemical features can help diagnose primary adenomatoid tumors of the adrenal gland.

A Rare Pancreatic Tumor with Adenomatoid Tumor-like Findings

A 74-year-old woman was referred to our hospital for the evaluation of slightly elevated tumor marker levels. Computed tomography revealed a well-demarcated tumor, approximately 15 mm in diameter, in the pancreatic tail. Endoscopic ultrasound-guided fine-needle aspiration findings suggested poorly differentiated cancer. The tumor was surgically resected, but postoperative pathologic confirmation was not possible. After one year without treatment and no recurrence, an evaluation by a specialized facility was requested for a definitive diagnosis. Adenomatoid tumor was deemed most likely based on the histopathology and immunostaining findings; however, a definitive diagnosis was difficult because of atypical findings. The patient was recurrence-free for 36 months at the last follow-up.

Multiparametric Ultrasound Diagnostic Approach to Malignancy-Mimicking Adenomatoid Tumors of the Scrotum: Is Strain Elastography Enough?

Background: Paratesticular tumors (PTs) are very uncommon, accounting for almost 5% of intrascrotal tumors. Of these, adenomatoid tumors (ATs) represent about 30% and most frequently arise in the tail of the epididymis. Ultrasound (US) examination is the first-choice imaging method employed for the evaluation of the scrotum. Unfortunately, there are no specific US-imaging features useful for distinguishing an AT from a malignant lesion. To increase diagnostic accuracy and confidence, new sonographic techniques have incorporated real-time tissue elastography (RTE) under the assumption that malignant lesions are "harder" than benign lesions. Case report: In our paper, we describe a very rare case of a 60-year-old patient with a giant paratesticular mass mimicking malignancy when examined using RTE, i.e., it was stiffer than the surrounding tissue (a hard pattern), which, upon histologic examination, was identified as an AT. Discussion: Our case underscores that there is also a significant overlap between different types of scrotal lesions when RTE is used for examination. Thus, if a PT is found, the imaging approach should always be supplemented with more definitive diagnostic methods, such as FNAC or FNAB, which are the only diagnostic methods capable of leading to a certain diagnosis. Conclusions: Alongside underlining the importance of pre-operative imaging for making correct diagnoses and selecting the correct therapy, we wish to draw our readers' attention to this report in order to demonstrate the clinical implications of a giant AT presenting as stiff lesions when examined using SE.

Pleural Neoplasms-What Could MRI Change?

The primary pleural neoplasms constitute around 10% of the pleural tumors. The currently recommended method for their imaging is CT which has been shown to have certain limitations. Strong development of the MRI within the last two decades has provided us with a number of sequences that could potentially be superior to CT when it comes to the pleural malignancies' detection and characterization. This literature review discusses the possible applications of the MRI as a diagnostic tool in patients with pleural neoplasms. Although selected MRI techniques have been shown to have a number of advantages over CT, further research is required in order to confirm the obtained results, broaden our knowledge on the topic, and pinpoint the sequences most optimal for pleural imaging, as well as the best methods for reading and analysis of the obtained data.

NR4A3 fusions characterize a distinctive peritoneal mesothelial neoplasm of uncertain biological potential with pure adenomatoid/microcystic morphology

A focal adenomatoid-microcystic pattern is not uncommon in peritoneal mesothelioma, but tumors composed almost exclusively of this pattern are distinctly rare and have not been well characterized. A small subset of mesotheliomas (mostly in children and young adults) are characterized by gene fusions including EWSR1/FUS::ATF1, EWSR1::YY1, and NTRK and ALK rearrangements, and often have epithelioid morphology. Herein, we describe five peritoneal mesothelial neoplasms (identified via molecular screening of seven histologically similar tumors) that are pure adenomatoid/microcystic in morphology and unified by the presence of an NR4A3 fusion. Patients were three males and two females aged 31-70 years (median, 40 years). Three presented with multifocal/diffuse and two with a localized disease. The size of the individual lesions ranged from 1.5 to 8 cm (median, 4.7). The unifocal lesions originated in the small bowel mesentery and the mesosigmoid. Treatment included surgery, either alone (three) or combined with hyperthermic intraperitoneal chemotherapy (two), and neoadjuvant or adjuvant chemotherapy (one case each). At the last follow-up (6-13 months), all five patients were alive and disease-free. All tumors were morphologically similar, characterized by extensive sieve-like microcystic growth with bland-looking flattened cells lining variably sized microcystic spaces and lacked a conventional epithelioid or sarcomatoid component. Immunohistochemistry confirmed mesothelial differentiation, but most cases showed limited expression of D2-40 and calretinin. Targeted RNA sequencing revealed an NR4A3 fusion (fusion partners were EWSR1 in three cases and CITED2 and NIPBL in one case each). The nosology and behavior of this morphomolecularly defined novel peritoneal mesothelial neoplasm of uncertain biological potential and its distinction from adenomatoid variants of conventional mesothelioma merit further delineation as more cases become recognized.

Mesotheliomas and Benign Mesothelial Tumors: Update on Pathologic and Imaging Findings

A diverse spectrum of benign entities and malignant neoplasms originate from the monotonous mesothelium that lines the serosal membranes of the pleural, pericardial, and peritoneal cavities. The mesothelium of myriad sites shows a common origin from the lateral plate mesoderm; primary mesothelial tumors thus demonstrate similar pathogenesis, imaging findings, and treatment options. Significant changes have been made in the 2021 World Health Organization (WHO) classification schemata of the pleural and pericardial tumors on the basis of recent advances in pathology and genetics. While malignant mesotheliomas are biologically aggressive malignancies that occur primarily in patients exposed to asbestos with attendant poor survival rates, well-differentiated papillary mesothelial tumors and adenomatoid tumors charter a benign clinical course with an excellent prognosis. Mesothelioma in situ is a newly characterized entity represented by recurrent unexplained pleural effusions without any identifiable mass at imaging or thoracoscopy. Immunohistochemical markers based on BAP1, MTAP, CDKN2A, and TRAF7 gene mutations help differentiate diffuse mesotheliomas from benign mesothelial proliferations and localized mesotheliomas. Cross-sectional imaging modalities, including US, CT, MRI, and fluorine 18-fluorodeoxyglucose (FDG) PET/CT, permit diagnosis and play a major role in staging and assessing surgical resectability. Imaging studies are invaluable in providing noninvasive and quantitative assessment of tumor response in patients with unresectable disease. Owing to significant overlap in patient characteristics and pathomorphology, accurate diagnosis based on advanced histopathology techniques and genetic abnormalities is imperative for optimal management and prognostication. While patients with nonepithelioid pleural mesotheliomas benefit from immunotherapy, novel targeted therapies for CDKN2A-, NF2-, and BAP1-altered mesotheliomas are under consideration. ^© RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Epididymal adenomatoid tumor: a case report and literature review

Background

Adenomatoid tumor is a very rare benign neoplasm of mesothelial origin affecting mainly female and male genital tracts. The diagnosis is challenging as this tumor mimics many differential diagnoses. The current literature offers only some case reports and short series of adenomatoid tumors.

Case presentation

A 47-year-old patient with unremarkable medical history presented for chronic mild pain of the right testis evolving for months. The physical examination shows a palpable right intrascrotal nodule of 10 mm in greatest diameter. The nodule was painful, mobile with firm consistency. The laboratory investigations were within normal limits, the scrotal ultrasonography showed a well-circumscribed predominantly hyperechoic intrascrotal nodule in the right epididymal head with heterogeneous echostructure. Excisional biopsy of the lesion was performed and the histopathological analysis showed a well-circumscribed tumor with microcystic and trabecular architecture made of small interconnected tubules and cysts lined by flattened cells with prominent vacuolization and thread-like bridging strands, consistent with an epididymal adenomatoid tumor. The postoperative course was uneventful and the patient was discharged. Four months after surgical treatment, the patient has no sign of the disease.

Conclusion

Testicular adenomatoid tumors are uncommon benign neoplasms with diagnostic challenge. Adenomatoid tumors arising in epididymis are managed by excisional biopsy with testis-sparing surgery avoiding unnecessary orchidectomy.

Localized Malignant Peritoneal Mesothelioma (LMPeM) in Women: A Clinicopathologic Study of 18 Cases

Localized malignant peritoneal mesothelioma is a rare tumor with limited information in the literature. In this study, we present our experience with 18 cases seen in our hospital over a period of 43 years (1978 to 2021). Patients' median age was 55 years (y) (range: 33 to 79 y) and most of them were Caucasians. Patients presented with abdominal pain (11), ascites and right leg swelling (1), abdominal mass (1), and as incidental finding (1). Thirty percent of patients reported asbestos exposure, and all patients with available information had family history of tumors; a third had personal history of tumors. Seventy-seven percent had some form of abdominopelvic surgery and/or inflammatory process. Most cases had microscopic features typically seen in malignant mesothelioma; however, some cases had confounding features such as signet-ring cells, spindle cells, clear cell changes, and adenomatoid tumor-like appearance. BAP-1 by immunohistochemistry was lost in 1/3 cases. Only 1 patient underwent genetic testing and had an MSH2 germline mutation. Homozygous deletion of CDKN2A by FISH was not found in 1 tested case, although next-generation sequencing identified a CDKN2A pathogenic mutation. 16/18 (88%) had surgical treatment, and some also received adjuvant chemotherapy. The mean overall survival (OS) of our patients was 80.4 months (95% confidence interval: 54.3-106.52); the 3-year OS was 79%, while the 5-year OS was 52.6%. Fifty-three percent of patients had recurrences and 20% had tumor progression. Although the limited sample precludes definitive conclusions, small tumor size, low-grade cytology, and low mitotic index appeared to be associated with an indolent behavior.

Peritoneal Pathology Review: Mullerian, Mucinous and Mesothelial Lesions

This review provides an overview of the pathology of selected benign and malignant lesions of the female peritoneum and their often-encountered differential diagnoses. It includes endometriosis and its related lesions, endosalpingiosis, pseudomyxoma peritonei (PMP) and related ovarian/appendiceal pathology, and malignant and benign mesothelial tumors. The current terminology associated with PMP is also discussed.

Inflammation of the Pleural Cavity: A Review on Pathogenesis, Diagnosis and Implications in Tumor Pathophysiology

Simple Summary

The pleura is a cavity whose pathology ranges from simple fluid accumulation to tumor development, all inducing important consequences in patents health, and usually having an important association with local inflammation. Understanding the pathophysiology of pleural inflammation helps the development of the correct treatment strategies and opens new windows in pleural research. Thus, the aim of this review is to present the etiologies and the pathophysiological mechanisms of pleural inflammation with a special interest in their role on tumor development and diagnosis.

Abstract

Pleural effusions are a common respiratory condition with many etiologies. Nonmalignant etiologies explain most pleural effusions and despite being nonmalignant, they can be associated with poor survival; thus, it is important to understand their pathophysiology. Furthermore, diagnosing a benign pleural pathology always harbors the uncertainty of a false-negative diagnosis for physicians and pathologists, especially for the group of non-specific pleuritis. This review aims to present the role of the inflammation in the development of benign pleural effusions, with a special interest in their pathophysiology and their association with malignancy.

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.

Malignant pleural mesothelioma: an update

Malignant mesotheliomas are rare types of cancers that affect the mesothelial surfaces, usually the pleura and peritoneum. They are associated with asbestos exposure, but due to a latency period of more than 30 years and difficult diagnosis, most cases are not detected until they reach advanced stages. Treatment options for this tumor type are very limited and survival ranges from 12 to 36 months. This review discusses the molecular physiopathology, current diagnosis, and latest therapeutic options for this disease.

[Adenomatoid tumor of the adrenal gland: Clinicopathologic characteristics and differential diagnosis on two tumors of exceptional adrenal location]

Adenomatoid tumors are benign tumors from mesothelial origin, usually occurring in the genital tract. Extragenital locations, especially in the adrenal gland are extremely rare. Here we are reporting two cases of a 28-year-old and 50-year-old men with an adenomatoid tumor of the right adrenal gland. Usual morphological aspects join scattered and microcystic pattern with epithelioid or signet-ring cells. According to the morphological features, main differential diagnoses are adenocarcinoma metastasis, vascular tumors or mesotheliomas. Immunohistochemistry provides precious help to confirm the mesothelial origin thanks to positivity of epithelial markers (CK7, AE1-AE3, CK5/6) coupled to mesothelial markers (D2-40, Calretinin, WT1). On the other hand, there is no loss of BAP1 by immunohistochemistry and usually a surexpression of P16. Adrenal gland adenomatoid tumor is a benign tumor, which can be promoted by iatrogenous or constitutive immunodepression.

Adenomatoid Tumor of Fallopian Tube With "Deciduoid" Morphology and Atypical Nuclear Features

Adenomatoid tumor is a benign neoplasm of mesothelial origin. Adenomatoid tumor in female genital tract shows typical morphologic features with bland nuclei. Deciduoid morphology has not been reported in adenomatoid tumor. Tumors with deciduoid cells and atypical nuclear features may pose a diagnostic challenge and raise the suspicion of malignancy. We present a case of fallopian tube adenomatoid tumor with deciduoid morphology and atypical nuclear features in a 39-year-old woman with prolonged progestin therapy. We hypothesize that the unusual morphological changes in adenomatoid tumor, like deciduoid morphology and nuclear atypia, may be secondary to hormone effects.

Adenomatoid Tumor of the Adrenal Gland: Report of Two Cases and Review of the Literature

Adenomatoid tumor (AT) is an uncommon benign neoplasm of mesothelial origin, usually occurring in the female and male genital tracts. Extragenital localization such as the adrenal gland is extremely rare. Until now, only 39 cases of adrenal AT have been reported in the English literature. Here we report two novel cases of adrenal AT that occurred in male patients aged 30 and 31 years. The tumors were discovered incidentally by computed tomography (CT). Macroscopically, the tumors were unilateral and solid, and the greatest dimension of the tumors was 3.5 and 8.0 cm, respectively. Histologically, the tumors consisted of angiomatoid, cystic, and solid patterns and infiltrated the adrenal cortical or medullary tissue. The tumor cells had low nuclear/cytoplasmic ratio, with no pathological mitosis or nuclear pleomorphism. Thread-like bridging strands and signet-ring-like cells could be seen. Immunohistochemically, the tumor cells were positive for epithelial markers (AE1/AE3, CK7) and mesothelial markers (D2-40, calretinin, and WT-1). The Ki-67 index was approximately 1 and 2%, respectively. The differential diagnosis of adrenal AT includes a variety of benign and malignant tumors. The patients had neither local recurrence nor distant metastasis at 21 and 8 months after removal of the tumor. In the literature review, we comprehensively summarized the clinical, morphological, immunohistochemical, and prognostic features of adrenal AT. Adrenal ATs are morphologically and immunophenotypically identical to those that occur in the genital tracts. Combining the histology with immunohistochemical profiles is very supportive in reaching the diagnosis of this benign tumor, helping to avoid misdiagnosis and overtreatment.