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Adenomatoid tumors (ATs) are rare, benign neoplasms occurring mainly in reproductive organs such as the uterus, ovaries, fallopian tubes, and testes. Uterine adenomatoid tumors (UATs) are generally incidentally diagnosed during histopathological examination of excisional biopsies performed for other indications, most commonly uterine leiomyomas. We herein present a 38-year-old woman who underwent laparoscopic excision of a uterine leiomyoma and a right ovarian teratoma. Microscopic examination of the excisional biopsy revealed that the enucleated uterine tumor was composed of proliferating glandular tissue covered with single-layered cells that were surrounded by proliferating smooth muscle cells, corresponding exactly to the features of UATs. The excised ovarian cyst was confirmed to be a typical mature cystic teratoma. According to these histopathological findings, the patient was finally diagnosed with a UAT and coexisting teratoma. No recurrence was detected up to 6 months after excision. To the best of our knowledge, this is the eighth case report on laparoscopically enucleated UATs. Although recurrence risk may be low in UATs, further case reports are necessary to elucidate the safety and validity of laparoscopic excision for UATs.

Adenomatoid tumors (AT) are usually found in the genital tract of both sexes. They are very rarely located in extragenital sites, and are exceedingly rare in the adrenal. AT of the adrenal gland (AT-AG) are nonfunctioning, usually discovered incidentally and confused on imaging with other more common adrenal neoplasms. The overwhelming majority occur in males. Thirty-four cases have been reported so far, more often presenting grossly as solid tumors, rarely as solid with cystic areas, and 5 cases were almost entirely cystic. At histology they can be either circumscribed or locally infiltrative, and may pose diagnostic difficulties when the pathologist relies on morphology alone or is challenged on frozen section. On light microscopy the diagnosis may be very difficult if the tumor is rich in vacuolated cells, mimicking metastatic signet ring-cell adenocarcinoma. Immunophenotyping and/or electron microscopy are paramount in helping to ascertain their mesothelial lineage. Lymphangioma is the main histologic mimic of solid-cystic and cystic AT-AG, but lymphangioma is immunopositive for endothelial markers and negative for cytokeratins and mesothelial markers. Ultrastructural analysis has been performed in 10 published cases of AT-AG, in all of which the classical microvilli of coelomic type were always observed. In brief we report herein the sixth case of cystic lymphangioma-like AT, which was incidentally discovered during clinical follow-up in a 39-year-old man undergoing cancer staging and surveillance after surgery. The adrenal tumor was 5.5 cm in size and was fully investigated immunohistochemically and ultrastructurally. A complete review of the literature is also presented.

The adenomatoid tumor is an uncommon benign lesion, thus far described only in humans. Adenomatoid tumors typically arise in the genital tract, exceptionally in the heart, and usually represent an incidental finding. Microscopically, they are constituted by epithelioid cells that form tubular structures and anastomosing channels within a fibrous stroma. Mesothelial origin of these lesions is suggested by their immunohistochemical characteristics. In cattle, previously reported myocardial epithelial inclusions are morphologically similar in that the cells are immunoreactive for both cytokeratins and vimentin, and bear surface microvilli. Myocardial lesions found incidentally at slaughter in 8 cattle histologically resembled the so-called bovine myocardial epithelial inclusions and had morphologic and immunohistochemical features consistent with human adenomatoid tumor. All lesions were in the left ventricular myocardium, adjacent to the epicardium, and composed of epithelioid cells that formed cords and tubules, and were immunoreactive for pan-cytokeratins, cytokeratin 5/6, vimentin, calretinin, Wilms' tumor 1 suppressor gene, and CD30 antigen. By electron microscopy, numerous long slender microvilli were associated with desmosomes and tonofibrils. The immunohistochemical and ultrastructural features were considered consistent with mesothelial origin. These lesions, corresponding to the previously described myocardial epithelial inclusions in cattle, might be considered embryologic rests and could represent the bovine counterpart of the human adenomatoid tumor.

Adenomatoid tumor of adrenal gland is a very rare primary tumor with favourable prognosis. The mesothelial origin of this tumor was confirmed by multiple studies of various authors. This origin was proven by immunohistochemical and ultrastructural examinations. In our case report, we present an interesting case of the adenomatoid tumor of the right adrenal gland in a 55-year-old woman. Our case is the second well-documented case of this tumor occurring in a female adult patient. We emphasize the presence of an intraluminal thread-like bridging strands, generally considered to be a characteristic histologic feature of this tumor, which have not yet been reported in literature in adenomatoid tumor located in adrenal glands.

A case of adenomatoid tumor presenting as a mass in the anterior mediastinum is described. The patient was a 56-year-old woman with left side chest wall pain who showed a mediastinal mass on chest x-ray and CT scans. Thorough clinical and radiographic examination did not reveal any evidence of tumor elsewhere. At surgery, the tumor was found adjacent to the anterior pericardial reflection. Grossly, the tumor measured 5.5 x 5.5 x 3 cm and showed a homogeneous cut surface with numerous cystic structures that varied from 0.5 to 1.5 cm in greatest diameter. Histologic examination showed numerous cystic spaces lined by flattened or cuboidal epithelial cells. The walls of the cysts showed a proliferation of small canalicular structures lined by round to polygonal epithelioid cells with vacuolated eosinophilic cytoplasm. Immunohistochemical studies showed strong positivity of the epithelioid cells for AE1/AE3 cytokeratin, CK5/CK6, and calretinin. Stains for CK7, CK20, alpha-fetoprotein, CD31, carcinoembryonic antigen, MOC 31, and chromogranin were negative. Electron microscopic examination showed numerous long microvilli on the cell surface and abundant tonofilaments/desmosomal plaques in the tumor cells, characteristic of mesothelial cells. The patient is alive and well and free of recurrence 1 year following surgery. Adenomatoid tumor is a rare neoplasm that should be added in the differential diagnosis of anterior mediastinal masses. Immunohistochemical and ultrastructural studies may be of aid in identifying the characteristic features of mesothelial cells and to avoid mistaking this lesion for more ominous conditions.

A case of diffuse adenomatoid tumor of the uterus in an immunosuppressed renal transplant recipient is reported and compared with two previously reported, similar cases. The multinodular uterine lesion grossly resembled intramural leiomyomata except for a mucoid cut surface and a cystic serosal component. The predominant patterns of the tumor were adenoid and angiomatoid with less prominent solid and cystic patterns. Immunohistochemical and ultrastructural studies confirmed the mesothelial nature of the tumor cells. Additionally, there was strong diffuse immunoreactivity for proliferating cell nuclear antigen, a low expression of Ki-67, and weak nuclear p53 staining. The relationship between immunosuppression and diffuse adenomatoid tumors is discussed.

We present rare case of a uterine adenomatoid tumor. In order to characterize the diversity of immunoreactive antigens associated with mesothelial differentiation, we immunohistochemically examined the tumor's epithelioid and myofibromatoid components, as well as the biphasic pattern of its adenomatoid changes. Immunostaining of tumor cells was positive for high- and low-molecular-weight cytokeratins and vimentin. Specific immunoreactions with antibodies against desmin, alpha-actin, and the S-100 protein also were observed. The present adenomatoid tumor can be explained in terms of various transformations and typical alterations in mesothelioma cells: (1) the mesothelial cells had differentiated to epithelial and stromal components, concomitant with the presence of predominant reactive foci; (2) intermediate cells expressed different types of cytoskeletal intermediate filament proteins (IMPs); and (3) the patterns of fibromatoid and leiomyoid differentiation resembled those of a benign mesothelioma of the ovarian or oviductal peritoneum. Our immunohistochemical investigations indicated that the present tumor exhibited the histogenesis of a true mesothelioma, an adenomatoid mesothelioma.

Adenomatoid tumor represents a type of mesothelioma apparently confined to the genital tract and characterized by its benign behavior. Its morphological aspects are well known and, until now, it has been described as a nodular mass except for a case diffusely infiltrating the entire myometrium in an immunosuppressed patient. We report a case of benign mesothelial tumor characterized by histological, immunophenotypical and ultrastructural features of an otherwise typical adenomatoid tumor but diffusely growing below uterine serosal surface into the myometrium without discernible borders. The existence of a diffuse type of adenomatoid tumor might reflect a different nature of this neoplasm leading to the hypothesis that this variant of benign mesothelioma represents a distinct biological entity.

Adenomatoid tumors arising in the uterus are not well-recognized and sometimes mistaken for other benign or malignant neoplasms. This study describes three cases of uterine adenomatoid tumors with clinical, light microscopic, histochemical and electron microscopical studies. Four distinctive histologic patterns (solid, adenoid, angiomatoid, cystic) were identified. Acid mucopolysaccharide was present in three cases and was digested by hyaluronidase. Immunohistochemically, tumor cells were positive for cytokeratin and vimentin. Electron microscopy revealed microvilli, intermediate filaments and dilated intercellular spaces. This gives further support to a mesothelial origin of the adenomatoid tumor. Interestingly, one case showed that the adenomatoid tumor was multiple and one nodule was connected with leiomyomatous nodule. In the other case, the tumor was large 5 x 4 x 4.5 cm). These features were unusual.

Five cases of adenomatoid tumors of the uterus (ATU) are reported. These benign lesions are discovered in 1% of the hysterectomy specimens, performed on 20- to 85-years-old women. Their frequency is certainly underestimated, since ATU have the same macroscopic appearance as leiomyomas. Histologically, ATU are formed by gland-like and pseudovascular lumens, lined by regular, cuboidal or flattened cells, and surrounded by hyperplastic smooth muscle bundles. Immunohistochemical coexpression of cytokeratin and vimentin confirms with a mesothelial histogenesis. The ultrastructural study, showing luminal microvilli and desmosomes supports the hamartomatous development of ATU, corresponding to mesothelial inclusions from the peritoneum into the myometrium. Some giant or diffuse ATU, which are clinically disturbing, are differentiated from carcinomatous or vascular proliferations by frozen section examination. The treatment is made by surgical excision.

In 2 cases of adenomatoid tumors of the uterus FVIII, keratin, vimentin and carcinoembryonic antigen (CEA) were observed by immunohistochemical method. No staining for FVIII and CEA were seen in the tumor cells but staining for keratin and vimentin were seen coexistent in the tumor cells. Electron microscopic finding showed tumor cells attached to one another by numerous long slender microvill. Adenomatoid tumors had typical mesothelial features. It suggests that adenomatoid tumor may be a mesothelioma.

Adenomatoid hyperplasia of minor salivary glands in an uncommon clinicopathologic entity, first reported, in 1971, by Giansanti and cols. The condition mimics a neoplasm because of its swelling, but the histologic picture agrees with that of normal appearing salivary gland tissue. The interest of this entity is that although benign pseudotumoral lesion, it can be clinically confused with benign or malignant tumors and even, through fine needle aspiration cytology, with low grade mucoepidermoid tumors. We present one case of this condition arising in the soft palate in a patient with unilateral serous otitis media. A review of the published literature on the subject is done.