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.

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.

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 tumor of the skin: Differential diagnosis of an umbilical erythematous plaque.

Adenomatoid tumors are benign tumors of mesothelial origin that are usually encountered in the genital tract. Although they have been observed in other organs, the skin appears to be a very rare location, with only one case reported in the literature to our knowledge. We report a second case of an adenomatoid tumor, arising in the umbilicus of a 44-year-old woman. The patient presented with an 8-month-old erythematous and firm plaque under the umbilicus. A skin biopsy showed numerous microcystic spaces dissecting a fibrous stroma and lined by flattened to cuboidal cells with focal intraluminal papillary formation. This little-known diagnosis constitutes a diagnostic pitfall for dermatopathologists and dermatologists, and could be misdiagnosed as other benign or malignant entities. Through this case report, a practical approach and diagnostic keys have been devised to avoid misdiagnosis and overtreatment.

Paratesticular tumors. A clinicopathological study from a single tertiary hospital in North India.

OBJECTIVE: Paratesticular tumors (PTT) are rare and form a heterogenous group, ranging from benign to malignant high grade sarcomas. This study was undertaken to describe the clinicopathological spectrum of PTTs received over a 20-year period. METHODS: All primary and secondary PTTs diagnosed from 2000 to 2019 in the pathology department of a tertiary care hospital in North India were retrospectively reviewed. Gross, histopathological features and immunohistochemistry (IHC) findings were correlated with clinical details. RESULTS: A total of 169 intra-scrotal tumors were diagnosed during the study period, out of which there were 30 PTTs (in 27 patients) comprising 17.75%. Age range was 4 to 85 years (median 58 years). Benign PTTs were the commonest (n = 21, 70%), followed by metastasis to the paratesticular region (n = 6, 20%) and then primary malignant PTTs (n = 3, 10%). The commonest benign PTT was lipoma (n = 16, 76.19%), followed by adenomatoid tumor (n = 3, 14.28%) with one case each (4.76%) of cellular angiofibroma and hemangioma. Among primary malignant PTT, there were two cases of rhabdomyosarcoma, and one case of biphasic malignant mesothelioma. Metastatic tumors included four cases of prostatic adenocarcinoma, and one case each of pancreatic signet ring cell carcinoma and clear cell renal cell carcinoma. CONCLUSION: PTTs show a wide clinicopathological spectrum. Benign PTTs are commoner than malignant PTTs. Meticulous grossing and histopathological examination supplemented by IHC is essential for an accurate diagnosis of this heterogenous class of tumors, which influences the role of adjuvant therapy and patient prognosis.

[Adenomatoid tumor of the adrenal gland: Clinicopathologic characteristics and differential diagnosis on two tumors of exceptional adrenal location]. / Tumeur adénomatoïde de la surrénale : aspects clinico-pathologiques et diagnostics différentiels de deux tumeurs de localisation surrénaliennes exceptionnelles.

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.

Well-differentiated papillary mesothelioma: A 17-year single institution experience with a series of 75 cases.

We present our experience with 75 cases of well-differentiated papillary mesothelioma (WDPM) that were diagnosed at our institution between 2000 and 2017. The patients included 58 females and 17 males with age ranging from 18 to 69 years (mean, 42 years). Clinically, the vast majority of WDPMs were incidental findings during laparotomy or laparoscopic surgery for a variety of benign or malignant disease. The lesion manifested as either a small solitary nodule or multiple miliary nodules on the peritoneum or serosal surfaces of internal organs. Histologically, 67 cases were consistent with a classical WDPM, of which 6 cases contained microinvasive foci and 1 case had malignant transformation. Eight cases were hybrid tumors with variable combined component of adenomatoid tumor (n = 4), multicystic mesothelioma (n = 2), and both (n = 2). By immunohistochemistry, besides calretinin, D2-40, CK5/6 and WT1, 94% (29/31) of cases also showed immunostaining for PAX8. In comparison, PAX8 staining was only present in 12% (6/50) of epithelioid malignant mesothelioma selected as control cases. Follow-up information available in 46 cases revealed no signs of tumor progression or local recurrence except for the case that showed transformation to a fully malignant mesothelioma after a period of 15 years. Our comprehensive study further expanded the clinical and histopathological spectrum of WDPM. Compared with epithelioid malignant mesothelioma, PAX8 staining is highly sensitive and specific for WDPM (P < 0.001).

Testis Sparing Surgery for Benign Testicular Masses: Diagnostics and Therapeutic Approaches.

PURPOSE: Small benign testicular masses are often misinterpreted as germ cell tumors and immediate inguinal orchiectomy is performed. We analyzed the diagnostic and therapeutic workup of testicular masses to improve preoperative stratification algorithms. MATERIALS AND METHODS: We performed a retrospective, single center analysis of the records of 522 patients diagnosed with primary testicular masses of unknown malignant potential. RESULTS: A total of 28 patients (5%) showed a primary benign tumor after resection, including Leydig cell tumors in 9 (32%), epidermoid cysts in 9 (32%), adenomatoid tumors in 8 (29%) and Sertoli cell tumors in 2 (7%). The median volume of benign tumors was significantly less than that of malignant tumors (0.75 cm3, range 0.1 to 2.1 vs 15, range 4.5-39.9, p ≤0.001). At a cutoff of 2.8 cm3 tumor volume most accurately differentiated between benign and malignant disease, and it was a predictor of malignancy with 83% sensitivity and 89% specificity (OR 1.389, 95% CI 1.035-1.864, p = 0.029). Symptom duration in patients with benign tumors was significantly longer (365 days, range 25.5 to 365 vs 20, range 7 to 42, p ≤0.001). Also, tumor markers were unaltered in benign lesions. In patients with benign tumors significantly more fertility disorders or cryptorchidism were found (p ≤0.001) as well as a tendency toward lower testosterone (3.9 µg/l, range 0.9 to 4.9 vs 5.3, range 3.5 to 6.8, p = 0.084). Testis sparing surgery was performed in 22 of all patients (79%) with benign tumors. There was no case of relapse during followup. CONCLUSIONS: Nongerm cell tumors should be considered when small testicular masses have a volume of less than 2.8 cm3 and there are hormone disorders or normal tumor markers. Immediate orchiectomy should be avoided, favoring testis sparing surgery.

A CASE OF ADRENAL ADENOMATOID TUMOR DIAGNOSED BY IMMUNOHISTOCHEMICAL EVALUATION.

An adenomatoid tumor is a benign tumor of mesothelial derivation, typically found in the genital track. However, though extremely rare, an adenomatoid tumor can be found in the adrenal gland, making it difficult to clinically and radiologically differentiate it from an adrenocortical tumor or a pheochromocytoma prior to surgery. We encountered a-52-year old man with an adenomatoid tumor in the adrenal gland, who presented with an incidentally discovered left adrenal mass revealed by PET-CT from his regular health examinations. He had been diagnosed with paroxysmal hypertension two years before and was being treated with a hypolipidemic agent. Abdominal computed tomography revealed a left adrenal mass measuring 25 × 15 mm, and the findings were different from the typical adrenocortical adenoma or pheochromocytoma. Although laboratory examinations of his blood samples indicated normal adrenal function, 24-hour urine specimens revealed high levels of 17-OHCS, 17-KS, and catecholamine. Both 131I-MIBG scintigraphy and phentolamine tests showed negative findings. The patient underwent a laparoscopic left adrenalectomy. The cut surface of the left adrenal gland weighing 21 g contained a white, solid mass measuring 25 × 15 × 20 mm within the adrenocortical tissue. Histologically, the tumor was composed of small tubules lined by eosinophilic tumor cells. The tumor cells were immunohistochemically positive for cytokeratins and calretinin, but negative for steroidogenic factor-1. Therefore, based on these findings, we diagnosed this tumor as an adrenal adenomatoid tumor. Histopathologically, the adrenal adenomatoid tumor may be difficult to distinguish from an adrenocortical adenoma, carcinoma, lymphangioma, hemangioma, angiosarcoma, or metastatic adenocarcinoma. Under these conditions, immunohistochemical examination is useful for definite diagnosis.

Adenomatoid tumor of the adrenal gland: unexpected guest.

Adenomatoid tumor (AT) is a benign growth that originates from mesothelial cells. Typically, it encompasses the uterus, fallopian tubes, and paratesticular area. One-third of all AT is in paratesticular area, and it accounts for 60% of all benign paratesticular tumors. ATs have been seldom reported as a case report in adrenal gland, liver, pleura, and mediastinal cavity. To date, English literature has only documented 46 instances of adrenal AT. We present the occurrence of a new clinically unexpected case of adrenal AT in a 37-year-old male patient. Computed tomography (CT scan) incidentally revealed the presence of a tumor. To the best of our knowledge, this is the first reported instance of primary adrenal gland AT reported in Saudi Arabia and the 47th instance worldwide in the English-based published literature. It is crucial to thoroughly investigate these tumors, utilizing techniques such as histopathological analysis and immunohistochemical staining to correctly diagnose AT.

MR Imaging Findings of Uterine Adenomatoid Tumors.

PURPOSE: Adenomatoid tumor is a rare benign genital tract neoplasm of mesothelial origin. Uterine adenomatoid tumors occur in the outer myometrium and may mimic leiomyomas. Because hormonal treatment is not applicable to adenomatoid tumors and laparoscopic enucleation is not easy as myomectomy, it is important to differentiate adenomatoid tumors from leiomyomas for the adequate treatment. The purpose of this study is to evaluate the MRI findings of adenomatoid tumor for the differentiation from leiomyoma. METHODS: MRI findings of surgically proven 10 uterine adenomatoid tumors in 9 women were retrospectively evaluated with correlation to histopathological findings. RESULTS: All 10 tumors appeared as solid myometrial masses and showed heterogeneous signal intensity with admixture of partially ill-defined slight high-intensity areas containing abundant tubular tumor cells and well-defined myoma-like low-intensity areas reflecting smooth muscle hypertrophy on T2WI including 4 lesions with peripheral ring-like high intensity. High-intensity areas on T2WI tended to show high intensity on diffusion-weighted imaging (DWI) with relatively high apparent diffusion coefficient (ADC), suggesting T2 shine-through effect due to abundant tubules. Intra-tumoral hemorrhage revealed on MRI was rare. Early intense contrast-enhanced areas on dynamic contrast-enhanced study were observed dominantly within the high-intensity areas but rarely within the low-intensity areas on T2WI. CONCLUSION: The outer myometrial mass with the admixture of well-defined low- and ill-defined high-intensity areas on T2WI may be suggestive of adenomatoid tumor. Peripheral ring-like high intensity on T2WI and DWI may also be suggestive. Dynamic contrast-enhanced MR study may be helpful for the differentiation from leiomyoma.

Adenomatoid tumor in a young male case report.

Adenomatoid tumors are benign para-testicular tumors and account for about 30% of all paratesticular neoplasms in males. The most common presentation is scrotal swelling between the third and fifth decades. We reported an epididymal adenomatoid tumor in a 28-year-old patient.

Staghorn Calculus with Adenomatoid Tumor: A Case Report.

Testicular adenomatoid tumor is very rare. More understanding of the tumor and treatment is required for better outcomes. A 63-year-old man visited a urologist for staghorn calculus. During follow-up, he had recurrent left flank pain and intermittent hematuria. Computed tomography demonstrated left staghorn calculus, and then further assessment revealed left testicular swelling. Ultrasound showed epididymal mass. Percutaneous nephrolithotomy was deferred and we performed left radical orchiectomy. A pathologic examination revealed testicular adenomatoid tumor. This case highlights the importance of awareness of a very rare benign tumor in a patient with staghorn calculus.

Diffuse WT1 Positivity in Smooth Muscle Component Supports Dual Differentiation of Mesothelial Cells in the Histogenesis of Leiomyoadenomatoid Tumors-A Report of two Cases.

Leiomyoadenomatoid tumors of the epididymis are exceedingly rare biphasic tumors composed of an adenomatoid component in the form of gland-like structures lined by single flat or cuboidal cells admixed with smooth muscle. Radiological and gross findings cannot distinguish leiomyoadenomatoid tumors from the more common classic adenomatoid tumors or leiomyomas, and careful microscopic examination is critical in the identification of this esoteric variant. The histogenesis of this entity remains ambiguous. Common hypotheses include a collision tumor, a variant of an adenomatoid tumor with a smooth muscle component, or an adenomatoid tumor arising in the background of reactive smooth muscle hyperplasia. We present 2 cases of leiomyoadenomatoid tumors with diffuse nuclear WT1 positivity in both the adenomatoid and smooth muscle components, supporting the mesothelial origin of these tumors.

An incidental finding of large cell calcifying Sertoli cell tumor in an orchidectomy specimen for a separate adenomatoid tumor.

Introduction: Large cell calcifying Sertoli cell tumors are exceedingly rare. They are most commonly benign, but risks for malignancy include older age, larger size of tumor, and solitary tumors. To the author's knowledge, this is the first case reported of an incidental large cell calcifying Sertoli cell tumor when an orchidectomy was performed for a separate lesion. Case presentation: A 31-year-old male presented with a painless testicular lump. Ultrasound demonstrated an exophytic lesion in the superolateral aspect and calcifications were noted inferomedially and inferolaterally in the right testis. On histology from radical orchidectomy, the superolateral lesion was found to be an adenomatoid tumor, and the calcifications inferiorly represented a large cell calcifying Sertoli cell tumor. The background showed foci of germ cell neoplasia in situ but no evidence of invasive malignancy. Conclusion: Calcifications on ultrasound in isolation may represent large cell calcifying Sertoli Cell tumors.

Adenomatoid tumor of the testis: A rare case report.

Adenomatoid tumors (AT) are benign tumors commonly found in paratesticular tissues. However, intratesticular AT are rare. Clinically and radiologically, the AT of the testis imitates the malignant neoplasia of the testis. Here, we present a case of the intratesticular AT.

Ultrasonography of a giant adenomatoid tumor of the tunica vaginalis: A case report and review of the literature.

Adenomatoid tumor is a kind of benign tumor, accounts for a low percentage of scrotal tumors. It usually locates in epididymis, less commonly, arises from the tunica albuginea, spermatic cord or tunica vaginalis of male's urogenital tract system. Here, we report a case of a 32-year-old male, which presented as a 6-month history of left scrotal swelling pain with a scrotal mass, and it had progressively enlarged over the last 1 month. The ultrasonography (US) described a giant well-defined hypoechoic mass in the left scrotum, a thick pedicle connected the mass and the left scrotal wall, and the pedicle had large blood vessels in it. Enhanced CT showed an irregular solid mass in the left scrotum, the left testicular artery was thickened to supply blood for the mass, and the radiologist mentioned it could not be excluded as a malignant lesion. The patient underwent left radical orchiectomy, the mass was diagnosed as an adenomatoid tumor of the tunica vaginalis by pathology. We review literature regarding adenomatoid tumors originating in the tunica vaginalis, summarize the ultrasonographic presentations, provide the idea of diagnosis and differential diagnosis to improve diagnostic accuracy and avoid unnecessary orchiectomy.

Adenomatoid mesothelioma arising from the diaphragm: a case report and review of the literature.

BACKGROUND: Adenomatoid mesothelioma is a rare subtype of malignant mesothelioma that can be confused with adenomatoid tumors, which are classified as benign. The clinical features and optimal management of adenomatoid mesothelioma have not been elucidated in the literature. In this report, we present an extremely rare case of adenomatoid mesothelioma that developed on the peritoneal surface of the diaphragm as well as a literature review of adenomatoid mesothelioma in the abdominal cavity. CASE PRESENTATION: The patient was a 61-year-old Japanese woman who had undergone resection of a malignant peripheral nerve sheath tumor of the hand 18 years prior. She was diagnosed with clinical stage I lung adenocarcinoma on follow-up chest radiography. Simultaneously, a 20-mm enhancing nodule with slow growth on the right diaphragm was detected on contrast-enhanced computed tomography. She presented no specific clinical symptoms. At this point, the lesion was suspected to be a hypervascular tumor of borderline malignancy, such as a solitary fibrous tumor. After a left upper lobectomy for lung adenocarcinoma, she was referred to our department, and laparoscopic tumor resection was performed. Adenomatoid tumors were also considered based on the histopathological and immunohistochemical analyses, but we made the final diagnosis of adenomatoid mesothelioma using the results of the genetic profile. The patient remains alive, with no recurrence noted 6 months after surgery. CONCLUSION: We encountered a valuable case of adenomatoid mesothelioma of peritoneal origin. There are some previously reported cases of adenomatoid mesothelioma and adenomatoid tumors that may need to be recategorized according to the current classification. It is important to accumulate and share new findings to clarify the clinicopathological characteristics and genetic status of adenomatoid mesothelioma.

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.

Peritoneal well-differentiated papillary mesothelioma associated with infertility in a 37-year-old woman.

Well-differentiated papillary mesothelioma (WDPM) is an uncommon mesothelial tumor. The lesions may be single or multiple and usually behave in a benign or indolent fashion, sometimes persisting for many years. In the present case, a 37-year-old woman had experienced primary infertility for 12 years, and a diagnostic laparoscopy was performed. Approximately 200 mL of dark red, free fluid in the pelvis and more than 10 yellow-white nodules on the surface of the right round ligament, sacrum ligament, right fallopian tube, and both sides of the uterus were found. A lesionectomy was performed and immunohistochemical markers indicated WDPM with adenomatoid tumor. The patient was monitored by computed tomography and serum CA125 (cancer antigen 125) levels for 49 months with no recurrence. WDPM and adenomatoid tumor are both benign tumors of mesothelial origin. Because of the lack of effective radical treatment, regular follow-up is sufficient. However, the effects of estrogen and progesterone on WDPM and adenomatoid tumors during ovulation or pregnancy remains unclear. Although WDPM is not life threatening, a strategy to fulfill the fertility requirements of women with this condition is a new challenge for infertility doctors.