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

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.

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.

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.

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.

Uterine adenomatoid tumor associated with lymph node lesions: a case report

We report a case of uterine adenomatoid tumor (AT) with regional lymph node involvement in a 49-year-old woman. Magnetic resonance imaging revealed an aggregated cystic mass in the posterior uterine wall with partial protrusion of the tumor outside the uterus, and cystic masses of same characteristics in the bilateral obturator and right common iliac lymph nodes. FDG PET/CT revealed no significant FDG uptake in the uterine and lymph node lesions. Taking possible lymph node metastasis into consideration, hysterectomy and lymph node biopsy were performed and it revealed AT of the uterus and the lymph nodes histopathologically.

Adenomatoid tumor of the small intestine: the first case report and review of the literature

The case represents the first literature report of an adenomatoid tumor that arises primarily in the small intestine of a 44-year-old woman, who presented with intermittent upper abdominal pain accompanied by nausea and vomiting. The resected tumor was grossly unencapsulated and had a gray-tan color on its cut surface. Microscopically, it consisted of variably sized tubules and glandular spaces which involved the whole layers of the intestine. The mesothelial nature of the lesion was subsequently verified by the immunopositivity for pancytokeratin (AE1/AE3), HBME-1, calretinin, D2-40, and WT1 with cells lining the tubules and glandular spaces. Albeit very rare, adenomatoid tumor should be included in the differential diagnosis of tubular or glandular tumors occurring in the small intestine.

Concurrent hepatic adenomatoid tumor and hepatic hemangioma: a case report

A 45-year-old male with alleged asymptomatic hepatic hemangioma of 4 years duration had right upper-quadrant pain and was referred to a tertiary hospital. Computed tomography and magnetic resonance imaging scans revealed a hypervascular mass of about 7 cm containing intratumoral multilobulated cysts. A preoperative liver biopsy was performed, but this failed to provide a definitive diagnosis. The patient underwent a partial hepatectomy of segments IV and VIII. The histologic findings revealed multifocal proliferation of flattened or cuboidal epithelioid cells and a highly vascular edematous stroma. Immunohistochemistry findings demonstrated that the epithelioid tumor cells were positive for cytokeratin (AE1/AE3), vimentin, calretinin, and cytokeratin 5/6, and were focally positive for CD10, and negative for WT1 and CD34, all of which support their mesothelial origin. Immunohistochemistry for a mesothelial marker should be performed for determining the presence of an adenomatoid tumor when benign epithelioid cells are seen.

Leiomyo-adenomatoid tumor of the uterus: a distinct morphological entity?

INTRODUCTION

The morphologic and immunohistochemical findings of a well-circumscribed leiomyoadenomatoid tumor located in the posterior uterine wall are reported.

CASE REPORT

The patient was a 55-year-old white woman who complained of peri/postmenopausal and irregular bleeding during the past 4 months. The adenomatoid component was intermingled with bland smooth muscle fascicles and was composed of vacuolated cells, tubules, and slit-like structures crossed by epithelial bridges. Immunohistochemistry revealed positivity to epithelial and mesothelial markers in the adenomatoid component and strong immunoreaction for smooth muscle markers in the leiomyomatous one.

CONCLUSIONS

The well-defined circumscription and the presence of mesothelial component intermingled with the leiomyomatous proliferation favors the hypothesis that a leiomyo-adenomatoid tumor should be considered as a subtype of adenomatoid tumor with distinctive morphological features. Only four previous cases of this rare neoplasm have been reported to date, one in the epydidimis and the other three cases in the uterine wall, one of them affecting also to the right ovary.

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.

Extrathoracic Mesothelial Proliferations and Their Mimics

Mesothelial proliferations, either reactive or neoplastic in nature, often pose difficult diagnostic dilemmas. Electron microscopy continues to be a gold standard in the identification of mesothelial differentiation. However, it is very common to apply long panels of antibodies for that purpose. In most cases, light microscopy and immunohistochemistry will solve the problem. However, the definitive, specific, and sensitive immunohistochemical marker is still lacking. This is particularly true in peritoneal and testicular mesothelial tumors, in which common embryologic origin with epithelial elements results in overlapping immunohistochemistry and morphology. The particularities of peritoneal and testicular mesothelial proliferations, and the main tumors that may mimic them in these sites, as well as the value and limitations of immunohistochemistry and electron microscopy in their differential diagnosis are the subject of this review.

Adenomatoid tumour of the liver

An unusual primary adenomatoid tumour arising in the normal liver is described. Hepatectomy was performed, and the patient is alive and free of disease 1 year postsurgery. Grossly, the tumour showed a haemorrhagic cut surface with numerous microcystic structures. Histological examination revealed cystic or angiomatoid spaces of various sizes lined by cuboidal, low-columnar, or flattened epithelioid cells with vacuolated cytoplasm and round to oval nuclei. The epithelioid cells were entirely supported by proliferated capillaries and arteries together with collagenous stroma. Immunohistochemical studies showed that the epithelioid cells were strongly positive for a broad spectrum of cytokeratins (AE1/AE3, CAM5.2, epithelial membrane antigen and cytokeratin 7) and mesothelial markers (calretinin, Wilms’ tumour 1 and D2-40). These cells were negative for Hep par-1, carcinoembryonic antigen, neural cell adhesion molecule, CD34, CD31 and HMB45. Atypically, abundant capillaries were observed; however, the cystic proliferation of epithelioid cells with vacuoles and immunohistochemical profile of the epithelioid element were consistent with hepatic adenomatoid tumour.

Review of endoscopic ultrasound-guided fine-needle aspiration cytology

This review, based on the Hennepin County Medical Center experience and review of the literature, vastly covers the up-to-date role of endoscopic ultrasonography (EUS) and EUS-guided fine-needle aspiration (FNA) in evaluating tumorous lesions of the gastrointestinal tract and adjacent organs. Emphasis is given to the tumoral and nodal staging of esophageal, pulmonary, and pancreatic cancer. This review also discusses technical, pathological, and gastroenterologic aspects and the role of the pathologist and endosonographer in the evaluation of these lesions, as well as the corresponding FNA cytology and differential diagnosis.

Adenomatoid tumor of the adrenal gland: case report with immunohistochemical study

Adrenal adenomatoid tumor (AT) is a recently recognized disease with marked male predominance. Herein is presented a case of adrenal AT incidentally found in a 30-year-old man and results of immunohistochemical examination of the tumor. The left adrenal gland, weighing 17 g, contained a mass measuring 3 x 2.5 x 2.5 cm in the cortical tissue. Cut surface showed a relatively well-circumscribed firm tumor with a white solid appearance. Histologically, the tumor had the typical appearance of AT described in the genital tract. Immunohistochemically, the tumor cells were positive for calretinin, D2-40, WT1, mesothelial cell antigen, CA125, thrombomodulin, vimentin and cytokeratins (stained by AE1 + AE3, OV-TL 12/30, CAM5.2 and MNF116), and negative for endothelial markers (CD31, CD34 and factor VIII-related antigen) and CD56. CD56-positive adrenocortical cells were diffusely scattered in the tumor, especially in its periphery. Immunohistochemistry of estrogen, progesterone and androgen receptors was negative. These findings confirm mesothelial origin of the tumor and suggest that this tumor has little relation to sex hormone despite male predominance.

Adenomatoid tumor of the adrenal gland: a clinicopathologic study of 3 cases

Adenomatoid tumors are relatively uncommon benign neoplasms of mesothelial origin, usually occurring in the male and female genital tracts. Rare extragenital adenomatoid tumors have been identified in the adrenal glands, heart, mesentery, pleura, and lymph nodes. In the adrenal gland, adenomatoid tumors may pose a diagnostic challenge. The differential diagnosis includes adrenocortical carcinoma and metastatic carcinoma, especially signet ring cell carcinoma. Because of its glandular pattern, an adenomatoid tumor may be confused with an adenocarcinoma. We present 3 cases of adrenal adenomatoid tumors, including one with a concurrent large hemorrhagic vascular adrenal cyst. The adenomatoid tumors were unilateral, appeared solid and white, and varied from 1.7 to 4.2 cm in diameter. They occurred in 3 male patients aged 33, 33, and 46 years. One patient presented with abdominal pain due to the presence of a concurrent large adrenal cyst. The tumor was an incidental radiological finding in another case and was discovered during the course of a workup for hypertension in the third case. The light microscopic appearances were consistent with those of typical adenomatoid tumors. Immunohistochemical stains for calretinin and cytokeratin 5/6 were positive, confirming the tumors' mesothelial origin. Ultrastructural studies performed in 2 cases revealed microvilli and desmosomes. Follow-up showed no evidence of recurrence or metastasis. In our experience, the key to the diagnosis of this rare benign tumor is to consider adenomatoid tumor in the differential diagnosis of any glandular tumor occurring in the adrenal gland.

Mesenchymale Tumoren des Pankreas

Mesenchymal tumors of the pancreas are rare. They are resected because a solid or cystic pancreatic tumor is suspected. Benign mesenchymal tumors comprise lymphangiomas, hemangiomas, schwannomas, solitary fibrous tumors, adenomatoid tumors, clear cell tumors, and hamartomas. Inflammatory pseudotumors are a special case. Malignant mesenchymal tumors include leiomyosarcomas, malignant peripheral nerve sheath tumors (MPNST), liposarcomas, malignant fibrous histiocytomas, Ewing's sarcomas, and primitive neuroectodermal tumors (PNET). It is important to differentiate these tumors from anaplastic carcinomas and retroperitoneal tumors that infiltrate pancreatic tissue.