Mixed adenoma-neuroendocrine tumor of the stomach: analysis of nine cases with literature review.

Mixed adenoma-neuroendocrine tumor (MANET) comprises adenoma and well-differentiated neuroendocrine tumor (NET) components. Given the limited information on this due to its rarity, we aimed to clarify the clinicopathologic features and optimal management of gastric MANETs in a case series and literature review. Nine patients with gastric MANETs, including eight male and one female patient (mean age, 72 years), were identified from the institutional pathology archive. Endoscopically, the tumors appeared as flat elevated lesions with sizes ranging from 0.8 to 4.4 cm. One patient had familial adenomatous polyposis, and no patient had autoimmune gastritis. All MANETs developed in the gastric body mucosa exhibiting chronic metaplastic atrophic gastritis. The glandular components were intestinal-type low-grade adenoma, and focal high-grade dysplasia was also recognized in three cases. The NET component was in middle/deep lamina propria in six cases and confined to deep lamina propria in the remaining three cases. Minimal cytologic atypia was found in the NET component, with no recognizable mitosis and a Ki-67 labeling index of < 2%. The NET component mostly showed diffuse positivity for serotonin and CDX2, suggesting that it consists of enterochromaffin cells. Diffuse p53 immunostaining was observed only in the high-grade adenomatous component of one case. No recurrence was observed during the follow-up period of 2-94 months. Correct distinction between the NET and poorly differentiated carcinoma components is crucial to prevent overtreatment of gastric MANETs. Considering its indolent nature, endoscopic resection is the primary recommendation for gastric MANETs as well as for pure adenomas.

Shared chromosome 21q loss in a mixed subtype renal cell carcinoma: composite or collision tumor?

Clear cell renal cell carcinoma (CCRCC) and papillary renal cell carcinoma (PRCC) are the two most frequently encountered subtypes of renal cell carcinoma (RCC). Rarely, these two entities are identified intermingled within the same mass and have been labeled either collision tumors juxtaposed by random chance or composite tumors that have arisen from a common tumorigenic precursor cell. Regarding this distinction, authors have commonly relied upon macroscopic, histologic, and clinicopathologic findings, which may be prone to subjectivity. Objective molecular evidence has been lacking. We present a renal tumor showing a mixed CCRCC and PRCC with corroborating histologic, immunophenotypic, chromosomal microarray analysis (CMA), and next-generation sequencing (NGS) analysis for the respective tumor components, including classic findings of chromosome 3p loss and VHL mutation within the CCRCC component and gain of chromosomes 7 and 17 within the PRCC component. Of novel interest, CMA revealed a shared loss of chromosome 21q in both components with no other identifiable shared or overlapping mutations. This report adds unique evidence supporting the possibility of a true composite renal cell carcinoma composed of two commonly recognized subtypes. This finding may help to inform early molecular pathogenetic mechanism of RCC tumorigenesis.

A Rare Case of Verrucous Carcinoma and Trichoblastoma of the Neck: A Case Report and Literature Review.

Verrucous carcinoma (VC) is a variant of cutaneous squamous cell carcinoma. This phenomenon mainly affects the oropharynx, genitalia, and soles of the feet. VC is a well-defined, exophytic, cauliflower-like growth that is warty in nature. Trichoblastoma is a benign epithelial tumor composed of follicular germinative cells. It presents as a small, smooth, non-ulcerated, skin-colored nodule on the scalp, neck, thigh, and perianal regions. The dual presentation of verrucous carcinoma and trichoblastoma of the neck is rare. Though treatment can be achieved through surgical resection, early detection offers a good prognosis. We present the case of a 54-year-old homeless male who presented with an unusual neck mass that was initially misidentified as an abscess. Surgical debridement was performed, and histopathological analysis revealed the presence of a rare combination of VC and trichoblastoma. This report highlights the challenges of this rare presentation, which may be overlooked or misdiagnosed as an abscess.

Metastatic Seeding From a Gastrointestinal Neoplasia in a Pituitary Adenoma: A Case Report and Literature Review.

Pituitary composite tumors consisting of metastasis within an adenoma are rare and aggressive entities. We present a case of esophageal adenocarcinoma metastasis at a prolactinoma presenting in a unique fashion and highlight how this case could contribute to a better understanding and early recognition of this condition. The patient was a 65-year-old male who presented with partial palsy of the third and sixth cranial nerves. He had a history of treated esophageal adenocarcinoma. He also had a known small parasellar lesion, with an elevated prolactin. Investigations showed a rapid progression of the parasellar lesion and normalization of prolactin. Partial surgical resection was performed, and pathology confirmed metastasis of the known digestive tract neoplasia. Although extremely rare, dual pathology of pituitary metastasis within adenomas should be considered in the differential diagnosis of sellar masses. Atypical behavior of benign adenomas, including rapid growth, spontaneous normalization of prolactin, or progression despite medical treatment should prompt medical teams to reconsider their diagnosis.

Vasoactive Intestinal Peptide-Secreting Pheochromocytoma: A Case Report and Review of Literature.

Objective: To describe a case of composite vasoactive intestinal peptide (VIP)-secreting pheochromocytoma and review literature to provide insight into the various presentations and potential management of these rare tumors. Case Report: A 64-year-old male patient presented with hypertensive emergency and coronary demand ischemia with development of watery diarrhea, hypokalemia, and achlorhydria syndrome. Serum and urine studies demonstrated elevated metanephrine and VIP levels. Definitive surgical resection resolved symptoms and normalized laboratory values. Pathologic examination of the specimen revealed pheochromocytoma with a Pheochromocytoma of the Adrenal gland Scaled Score of 4 and patchy expression of VIP. Discussion: Given the different actions of hormones that can be secreted by these composite tumors, we suggest that pheochromocytomas with diversified secretory capabilities may be an underrecognized clinical entity. Localized disease is often amenable to surgical resection, although management of metastatic disease is not well established due to the rarity of these tumors and lack of randomized trials. Conclusion: In patients presenting with diarrhea of unclear etiology or the suggestion of secondary hypertension, assessment for a possible neuroendocrine tumor may be prudent. If an adrenal mass is discovered but the patient exhibits atypical symptoms of catecholamine excess, a diagnosis of composite pheochromocytoma with multisecretory properties should be considered.

Coexistence of carcinoid tumor and adenocarcinoma of the lung; morphological, immunohistochemical and genetic analyses, a case report.

BACKGROUND: Pulmonary carcinoid tumors rarely coexist with non-small cell lung carcinoma, and only nine cases have been reported previously. The pathogenesis and origin of these combined tumors remain unclear because of its rarity. CASE PRESENTATION: We examined two cases of adenocarcinoma coexisting with a typical or atypical carcinoid tumor: Case 1 was a 77-year-old woman and Case 2 was an 83-year-old woman. Both of these cases had no respiratory symptoms, and underwent pulmonary lobectomies due to incidentally detected lung nodules. Recurrence and metastases were not detected after the surgery. Histologically, carcinoid and adenocarcinoma components were present in both cases. The two components coexisted without mixing with each other. Next-generation sequencing was performed on the two components in these cases. In each case, no common genetic variants were detected. CONCLUSION: We considered that our cases could histologically and genetically represent collision tumors that did not share common progenitor cells. Comprehensive analyses such as whole genome sequencing could provide important information for elucidating the pathogenesis of adenocarcinoma and carcinoid components.

Oncogenic FGFR1 mutation and amplification in common cellular origin in a composite tumor with neuroblastoma and pheochromocytoma.

Neuroblastoma (NB) and pheochromocytoma (PCC) are derived from neural crest cells (NCCs); however, composite tumors with NB and PCC are rare, and their underlying molecular mechanisms remain unknown. To address this issue, we performed exome and transcriptome sequencing with formalin-fixed paraffin-embedded (FFPE) samples from the NB, PCC, and mixed lesions in a patient with a composite tumor. Whole-exome sequencing revealed that most mutations (80%) were shared by all samples, indicating that NB and PCC evolved from the same clone. Notably, all samples harbored both mutation and focal amplification in the FGFR1 oncogene, resulting in an extraordinarily high expression, likely to be the main driver of this tumor. Transcriptome sequencing revealed undifferentiated expression profiles for the NB lesions. Considering that a metastatic lesion was also composite, most likely, the primitive founding lesions should differentiate into both NB and PCC. This is the first reported case with composite-NB and PCC genetically proven to harbor an oncogenic FGFR1 alteration of a common cellular origin.

Focal nodular hyperplasia associated with a giant hepatocellular adenoma: A case report and review of literature.

BACKGROUND: Focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) are well-known benign liver lesions. Surgical treatment is usually chosen for symptomatic patients, lesions more than 5 cm, and uncertainty of diagnosis. CASE SUMMARY: We described the case of a large liver composite tumor in an asymptomatic 34-year-old female under oral contraceptive for 17-years. The imaging work-out described two components in this liver tumor; measuring 6 cm × 6 cm and 14 cm × 12 cm × 6 cm. The multidisciplinary team suggested surgery for this young woman with an unclear HCA diagnosis. She underwent a laparoscopic left liver lobectomy, with an uneventful postoperative course. Final pathological examination confirmed FNH associated with a large HCA. This manuscript aimed to make a literature review of the current management in this particular situation of large simultaneous benign liver tumors. CONCLUSION: The simultaneous presence of benign composite liver tumors is rare. This case highlights the management in a multidisciplinary team setting.

Carcinoma with Triphasic Differentiation Arising from Inverted Papilloma in Sinonasal Sinus: A Rare Case with Molecular Characterization.

Small cell neuroendocrine carcinoma (SNEC) is a rare subset of tumors in the sinonasal sinus. Combined tumors are exceedingly rare. Here, we describe a 65-year-old male with a mixed tumor of SNEC and sarcomatoid carcinoma arising in an inverted papilloma, containing squamous cell carcinoma in situ (SqCCis) in the sinonasal sinus. We evaluated the molecular characteristics of the two separate carcinoma components using next-generation sequencing. The patient presented with a nasal obstruction. Computed tomography showed a mass infiltrating the right ethmoid and maxillary sinuses. An excisional biopsy was performed. The tumor was found to have three morphologically distinct components. The first was SqCCis arising in an inverted papilloma, which was positive for cytokeratin and P40. The second consisted of nests of densely packed small round cells representing SNEC-positive neuroendocrine markers. The third was a solid sheet of anaplastic spindle cell proliferation, which was negative for the above markers. Oncogenic mutations such as FBXW7, TP53, and EGFR were detected in both SNEC and sarcomatoid carcinoma, and MYCL amplification was observed only in the SNEC component. This case highlights an extremely rare presentation of combined SNEC and sarcomatoid carcinoma arising from an inverted papilloma in the sinonasal sinus.

A Gastric Intramucosal Mixed Adenocarcinoma-Neuroendocrine Tumor.

Gastric mixed adenocarcinoma-neuroendocrine tumor (NET) is a rare composite tumor, and a limited number of studies have reported on it. A 77-year-old man was admitted to our hospital because of acute cholecystitis. He underwent a cholecystectomy. Esophagogastroduodenoscopy during his admission revealed a slightly elevated tumor, and biopsy demonstrated a well-differentiated tubular adenocarcinoma. The tumor was resected completely by endoscopic submucosal dissection. Histological findings showed that it measured 9 mm in diameter, was located within the mucosa, and consisted of well-differentiated tubular adenocarcinoma and a NET G1. The NET was covered with adenocarcinoma and both components exhibited histological continuity. The NET and a part of the adenocarcinoma component showed a positive reaction for chromogranin A and synaptophysin. Neither enterochromaffin-like cell hyperplasia nor endocrine cell micronest surrounded the tumor. The diagnosis was gastric mixed adenocarcinoma-NET. The histological continuity between the two components can be likened to the same histogenesis.

Does Mixed Neuroendocrine-Nonneuroendocrine Neoplasm (MiNEN) of the Parathyroid Gland Exist? First Description of a Possible Case.

We describe the histological, histochemical, and immunohistochemical features of an unusual neoplasm of the parathyroid gland showing the histologic criteria of a mixed neuroendocrine-nonneuroendocrine neoplasm (MiNEN). To the best of our knowledge, this is the first report of such a tumor. A 43-year old male presented with acute and severe abdominal pain due to acute pancreatitis. On physical examination a painless lump in the right neck was detected and laboratory analyses revealed hyperparathyroidism (parathormone: 146 pmol/L, normal range 1.05-6.83) and hypercalcemia (calcium level: 3.02 mg/dL, normal range 2.25-2.5), which fell to 2.55 mg/dL after parathyroidectomy. Histologically, the tumor was a parathyroid carcinoma associated with a mucous secreting adenocarcinoma also confirmed by histochemical (Alcian blue-periodic acid Schiff) and immunohistochemical stainings. The present case expands the spectrum of MiNENs that can be found in endocrine organs.

Ovarian yolk sac tumor with epithelial tumor component in a postmenopausal woman - case report and literature review.

Ovarian yolk sac tumors are common germ cell tumors usually arising in young women. Yolk sac tumors in elderly women are infrequently encountered and most of them are combined with other epithelial tumor components including endometrioid carcinoma or serous carcinoma. Here, we report an extremely rare case of a yolk sac tumor with mucinous tumor and large cell neuroendocrine carcinoma components in a postmenopausal woman, which is the third yolk sac tumor case with a neuroendocrine tumor element in an elderly woman. An 82-year-old female visited our hospital due to abdominal distention. Abdominal computed tomography (CT) demonstrated a solid and cystic mass, measuring about 9.0 cm in the largest diameter. A total hysterectomy with bilateral salpingo-oophorectomy and excisional biopsy of the peritoneal metastatic lesions was performed. Histologic evaluation revealed a malignant ovarian tumor composed of a variety of tumor components, including a yolk sac tumor, a mucinous tumor with multifocal mucinous carcinomatous areas, and a large-cell neuroendocrine carcinoma. After surgery, the patient refused further treatment and the disease recurred in the pelvic peritoneum and a left supraclavicular lymph node nine months later.

Bowen disease with invasive mucin-secreting sweat gland differentiation: Report of a case and review of the literature.

Bowen disease (BD) with divergent adnexal differentiation is a rare composite cutaneous tumor featuring different phenotypic elements. Sebaceous, poroid and trichilemmal invasive components have been described in this setting and very infrequent reports of mucinous glandular differentiation are extant. Clinically, these tumors are not sufficiently distinctive to enable recognition without histopathological evaluation. From a microscopic perspective, care must be taken to exclude a collision tumor as well as other combined cutaneous neoplasms featuring squamous and glandular differentiation. Direct continuity between the two epithelial phenotypes helps to establish the correct diagnosis and generates interesting speculation about the pathogenesis of these and other epithelial skin tumors. We describe a case of BD in continuity with an invasive adenocarcinoma exhibiting mucinous sweat gland differentiation on the face of an elderly man. Details of the case are outlined with the objective of adding to a scant literature on this topic.

The role of next-generation sequencing in the differential diagnosis of composite neoplasms.

Composite neoplasms (CNs) are rare and diagnostically challenging lesions that require differentiating between mixed clonal tumors with divergent phenotypes (MT), collision of 2 independent tumors adjacent to each other (CT), and tumor-to-tumor metastasis (TTM). To that end, pathologists have traditionally used immunohistochemistry and limited molecular studies, such as Sanger sequencing. Herein we evaluate the potential application of NGS in the differential diagnosis of these rare neoplasms. Four CNs were included in the study. Two were diagnosed as MT (mixed adenoneuroendocrine carcinoma of the gallbladder and metastatic papillary thyroid carcinoma with squamous dedifferentiation) and 2 were interpreted as TTM (esophageal adenocarcinoma to lung adenocarcinoma and small cell carcinoma of the lung to meningeal melanoma). Diagnoses were made using clinical, histologic, and immunophenotypic information, with the aid of limited molecular studies in 2 cases. Formalin-fixed, paraffin-embedded tissue was dissected for DNA and RNA extraction, and NGS was performed using the Oncomine Comprehensive Panel. The 2 tumors initially interpreted as MT showed shared genetic aberrations in the different neoplastic components, supporting the pathologic diagnosis. NGS results for the lesion diagnosed as esophageal adenocarcinoma metastatic to lung adenocarcinoma did not support the histopathologic interpretation and were deemed inconclusive. However, the identification of an identical CDKN2A mutation in all components and in the adjacent benign lung parenchyma suggests a possible germline aberration. Sequencing results in the last case were clearly supportive of TTM. This study illustrates the role of NGS in the diagnostic workup of CNs, as an adjunct to light microscopy and immunohistochemistry.

Composite trichoblastoma and inverted follicular keratosis: a case report.

Composite trichoblastoma and inverted follicular keratosis is extremely rare and the histogenesis is unclear. To date, only four cases have been described in a report. We report a case of 62-year-old woman patient with a palpable cutaneous nodule on the buttock. The patient had a history of squamous cell carcinoma on the lower lip 13 months ago. Excisional biopsy was done, and the microscopic examination revealed composite tumor of trichoblastoma and inverted follicular keratosis. The patient has not been experienced recurrence after surgery.

Malignant lymphoma arising in cardiac myxoma, presenting with peripheral arterial emboli.

Composite tumors of cardiac myxoma and malignant lymphoma are extremely rare, with 11 of such cases reported in the literature. A 44-year-old man presented to us with abrupt right lower leg pain. A computed tomography angiogram revealed segmental obstruction of the right common femoral artery, and embolectomy was performed. The embolectomy specimen contained several clusters of degenerated round/oval atypical cells in the fibrinous or myxoid background. Immunohistochemical examination revealed that these atypical cells were negative for cytokeratin and non-specifically expressed CD45. After one year of follow-up, the patient presented with dyspnea on exertion. Transthoracic echocardiography revealed a 5.7×1.9 cm, lobulated, echogenic, intracardiac mass, and excision was performed. Microscopically, most of the mass was composed of stellate or curved cells with eosinophilic cytoplasm in the myxoid background. However, several clusters or scattered round/oval atypical cells, similar to those observed in the embolectomy specimen, were observed. These atypical cells were positive for CD45 and CD20, with a Ki-67 labeling index of 90%. Calretinin was expressed in stellate cells but not in atypical cells. Therefore, we made a diagnosis of diffuse large B cell lymphoma (DLBCL) arising in the cardiac myxoma. Our case is an extremely rare example of a composite tumor of cardiac myxoma and DLBCL presenting with peripheral arterial emboli. Thorough histological evaluation of embolectomy and cardiac myxoma specimen is crucial for the diagnosis of composite tumor.

Mixed Neuroendocrine-Nonneuroendocrine Neoplasms (MiNENs): Unifying the Concept of a Heterogeneous Group of Neoplasms.

The wide application of immunohistochemistry to the study of tumors has led to the recognition that epithelial neoplasms composed of both a neuroendocrine and nonneuroendocrine component are not as rare as traditionally believed. It has been recommended that mixed neuroendocrine-nonneuroendocrine epithelial neoplasms are classified as only those in which either component represents at least 30 % of the lesion but this cutoff has not been universally accepted. Moreover, since their pathogenetic and clinical features are still unclear, mixed neuroendocrine-nonneuroendocrine epithelial neoplasms are not included as a separate clinicopathological entity in most WHO classifications, although they have been observed in virtually all organs. In the WHO classification of digestive tumors, mixed neuroendocrine-nonneuroendocrine neoplasm is considered a specific type and is defined as mixed adenoneuroendocrine carcinoma, a definition that has not been accepted for other organs. In fact, this term does not adequately convey the morphological and biological heterogeneity of digestive mixed neoplasms and has created some misunderstanding among both pathologists and clinicians. In the present study, we have reviewed the literature on mixed neuroendocrine-nonneuroendocrine epithelial neoplasms reported in the pituitary, thyroid, nasal cavity, larynx, lung, digestive system, urinary system, male and female genital organs, and skin to give the reader an overview of the most important clinicopathological features and morphological criteria for diagnosing each entity. We also propose to use the term "mixed neuroendocrine-nonneuroendocrine neoplasm (MiNEN)" to define and to unify the concept of this heterogeneous group of neoplasms, which show different characteristics mainly depending on the type of neuroendocrine and nonneuroendocrine components.

Composite Epstein-Barr Virus-Associated B-Cell Lymphoproliferative Disorder and Tubular Adenoma in a Rectal Polyp.

Composite tumors are formed when there is intermingling between two components of separate tumors seen histologically. Cases demonstrating composite tubular adenoma with other types of tumors in the colon are rare. Composite tubular adenomas with nonlymphoid tumors including carcinoids, microcarcinoids, and small cell undifferentiated carcinoma have been reported in the literature. The occurrence of composite lymphoma and tubular adenoma within the colorectal tract is extremely rare. Only three cases have been reported and include one case of mantle cell lymphoma and two cases of diffuse large B-cell lymphoma arising in composite tubular adenomas. We present the first case of composite Epstein-Barr virus-associated B-cell lymphoproliferative disorder and tubular adenoma in a rectal polyp with a benign endoscopic appearance.

Composite Tumor Associating Trichoblastoma and Seborrheic Keratosis.

Seborrheic keratosis is a common benign epidermal tumor histologically composed of basaloid and squamous cells. It mainly occurs on the face, scalp, and trunk, and presents clinically as a well-circumscribed, brownish to black papule, nodule, or plaque. Trichoblastoma is a relatively rare benign, slow-growing tumor showing differentiation toward the primitive hair follicle. It clinically manifests as a solitary, skin to erythematous colored, well-circumscribed dermal nodule located predominantly on the head and neck with a predilection for the scalp. Histologically, a well-demarcated mass of follicular germinative cells that show various degrees of differentiation, arranged in lobules, sheets, and nests, is located in the dermis or subcutaneous fat layer. We report the case of a 28-year-old female patient with a solitary, 2.0×4.0-cm black plaque with a 0.7-cm skin-colored nodule on the scalp. Histologically, the entire black plaque had prominent hyperkeratosis, acanthosis, and papillomatosis with horn cysts. The central nodule showed well-circumscribed, various-sized dermal tumor lobules without a connection to the overlying epidermis. The lobular aggregation was composed of numerous basaloid epithelial nests and multiple primitive papillary structures with distinct peripheral palisading of nuclei. According to these findings, the scalp lesion was diagnosed as a composite tumor associating trichoblastoma and seborrheic keratosis.