Acinar Cell Carcinoma of the Pancreas

A case of acinar cell carcinoma of the pancreas is presented. The differential diagnosis is discussed and includes endocrine neoplasm of the pancreas (islet cell and carcinoid tumor) and a poorly differentiated adenocarcinoma. The separation of the various entities by light microscopic, histochemical, immunocytochemical, and ultrastructural methods is described. The acinar cell carcinoma characteristically is positive for pancreatic digestive enzymes by immunocytochemistry, and at the ultrastructural level zymogen-type granules can be demonstrated; these have a tendency to aggregate in the apical region of acinar structures. Clinically the acinar cell carcinoma is an aggressive malignant neoplasm that may present with a characteristic syndrome of disseminated fat necrosis. Survival is generally less than 1 year.     

Helioid Inclusions in Dedifferentiated Acinic Cell Carcinoma of the Parotid Gland

Helioid bodies are exceedingly rare, intranuclear, rounded inclusions with peripheral radiating filaments. These structures, which were formerly observed in only three cases of proliferative breast epithelial lesions, appeared in 0.5–1% of the neoplastic cells of a case of dedifferentiated acinic cell carcinoma of the parotid gland. Helioid bodies are related to rough endoplasmic reticulum cisternae, which suggests that they are the result of the condensation and partial crystallization of their contents when sequestrated into the nuclear compartment of the cell. The presence of helioid bodies may be related to secretory dysfunction of the tumor cells associated with the process of neoplastic dedifferentiation.     

Helioid Inclusions in Dedifferentiated Acinic Cell Carcinoma of the Parotid Gland

Helioid bodies are exceedingly rare, intranuclear, rounded inclusions with peripheral radiating filaments. These structures, which were formerly observed in only three cases of proliferative breast epithelial lesions, appeared in 0.5-1% of the neoplastic cells of a case of dedifferentiated acinic cell carcinoma of the parotid gland. Helioid bodies are related to rough endoplasmic reticulum cisternae, which suggests that they are the result of the condensation and partial crystallization of their contents when sequestrated into the nuclear compartment of the cell. The presence of helioid bodies may be related to secretory dysfunction of the tumor cells associated with the process of neoplastic dedifferentiation.     

Small Cell Undifferentiated Carcinoma of the Pancreas

Small cell undifferentiated carcinoma of the pancreas is a rare neoplasm: Only 12 cases have previously been documented. This paper describes the clinical evolution, immunohistochemical profile, and ultrastructural features of a case occurring in a 37-year-old woman.     

Acinar Cell Carcinoma of the Pancreas

Four cases of acinar cell carcinoma of the pancreas are reported. An acinar cell carcinoma can resemble an islet cell tumor by routine light microscopy but the two differ considerably in their fine structure and immunostaining properties. Although cells of both tumors contain numerous dense-core granules, their size ranges are different, and atypical forms occur in the acinar cell tumors, including elongated bodies filled with filaments. Many mitochondria-rough endoplasmic reticulum complexes were present in one tumor. In a liver metastasis, nests of endocrine cells were discovered amid the groups of acinar cells, and some of the endocrine granules contained rectangular cores.     

Filamentous Inclusions in Nonneoplastic and Neoplastic Pancreas: An Ultrastructural and Immunogold Labeling Study

Filamentous inclusions (F1) are unusual, irregularly shaped cytoplasmic inclusions, which are mostly found in acinar cell carcinomas of the pancreas and are consequently thought to be an abnormal zymogen granule type. This study describes identical inclusions in acinar, centroacinar, and small duct epithelial cells from nonneoplastic pancreas, as well as those found in tumor cells from a mixed acinar-endocrine pancreatic carcinoma. An ultrastructural and immunogold labeling demonstration indicates that these inclusions are aggregates of intermediate filaments immunoreacting with the anti-cyto-keratin AE1/AE3 mixture and with V9 clone anti-vimentin monoclonal antibodies. Their pleomorphic appearance, variable immunoreactivity, and frequent association with lipid droplets and secondary lysosomes, mostly of the angulate type, led to the hypothesis that the F1 undergo a degenerative remodeling pathway similar to that proposed for hepatic Mal-lory bodies. A survey of the literature on Fl and human tumors suggests that they are a variably expressed ultrastructural feature of tumor cells originating from exocrine cell-containing tissues, namely the pancreas and gastrointestinal tract.     

Filamentous Inclusions in Nonneoplastic and Neoplastic Pancreas: An Ultrastructural and Immunogold Labeling Study

Filamentous inclusions (F1) are unusual, irregularly shaped cytoplasmic inclusions, which are mostly found in acinar cell carcinomas of the pancreas and are consequently thought to be an abnormal zymogen granule type. This study describes identical inclusions in acinar, centroacinar, and small duct epithelial cells from nonneoplastic pancreas, as well as those found in tumor cells from a mixed acinar-endocrine pancreatic carcinoma. An ultrastructural and immunogold labeling demonstration indicates that these inclusions are aggregates of intermediate filaments immunoreacting with the anti-cyto-keratin AE1/AE3 mixture and with V9 clone anti-vimentin monoclonal antibodies. Their pleomorphic appearance, variable immunoreactivity, and frequent association with lipid droplets and secondary lysosomes, mostly of the angulate type, led to the hypothesis that the F1 undergo a degenerative remodeling pathway similar to that proposed for hepatic Mal-lory bodies. A survey of the literature on Fl and human tumors suggests that they are a variably expressed ultrastructural feature of tumor cells originating from exocrine cell-containing tissues, namely the pancreas and gastrointestinal tract.     

Small Cell Neuroendocrine Carcinoma of the Urinary Bladder: Report of Three Cases with Ultrastructural Analysis

Three cases of small cell neuroendocrine carcinoma of the urinary bladder were studied by light and electron microscopic techniques. Dense-core, membrane-bound granules were identified in the cytoplasm of all 3 cases, substantiating the light microscopic impression of a morphologic similarity to other neuroendocrine carcinomas, such as small cell (oat cell) carcinoma of the lung. Two of the three cases showed clinical evidence of distant metastases, suggesting an aggressive biologic potential of this tumor similar to oat cell carcinoma of the lung. A partial remission was induced in these 2 cases using chemotherapy protocols similar to the drug regimens for small cell (oat cell) carcinomas of the lung. Recognition of this distinct entity has important clinical implications regarding therapeutic approach.     

Acinar cell carcinoma arising in the stomach: a case report with literature review

Acinar cell carcinomas (ACCs) are uncommon malignant tumors of the exocrine pancreas, constituting 1% to 2% of all nonendocrine pancreatic neoplasms. Cases of acinar cell carcinoma developing in heterotopic pancreatic tissue are extremely rare. To the best of our knowledge, no cases of primary ACC developing in the stomach have been reported in the literature. We report the first case of a primary ACC arising in the stomach in an 86-year-old female who presented with a 5-cm gastric submucosal mass with superficial ulceration and a history of anemia. The neoplasm exhibited typical acinar morphology. Immunohistochemical studies demonstrated strong positive reactivity for antitrypsin and antichymotrypsin, and electron microscopy confirmed the presence of zymogen granules. A complete metastatic workup failed to identify any primary pancreatic tumor or other nonpancreatic tumor.     

Dual Differentiation in Small Cell Carcinoma (Oat Cell Carcinoma) of the Lung

Two cases of small cell “undifferentiated” carcinoma (oat cell carcinoma) of the lung with dual neurosecretory and squamous differentiation are reported. One was treated with various regimens of chemotherapy and radiotherapy; the other was untreated at the time of biopsy. By electron microscopy, the same tumor cells showed membrane-bound, dense-core, neurosecretory-type granules and bundles of tonofibrils denoting squamous differentiation. This dual differentiation underlies the difficulty of ascribing an exclusively neural histogenesis to small cell carcinomas with neurosecretory-type granules. It is possible that entoderm-associated neuroectodermal tumors develop features of autochthonous entodermal tumors as a result of microenvironmental influences. An alternative hypothesis would be that small cell tumors are derived from basal reserve bronchoepithelial cells with pluripotentialities.     

Crystals and Alpha-1-Antitrypsin-Reactive Globoid Inclusions in an Islet Cell Tumor of the Pancreas

An islet cell tumor of the pancreas with unusual light microscopic, ultrastructural, and immunocyto-chemical features is reported. In addition to secretory granules and positive immunostaining for pancreatic polypeptide, the tumor contained globoid intracytoplasmic inclusions by light and electron microscopy, which correlated with a positive immunoreaction for alpha-1-antitrypsin, and Reinkelike crystals.     

Glycogen-rich Clear Cell Carcinoma of the Urethra: An Ultrastructural Study

A 49-year-old black woman developed a urethral glycogen-rich clear cell carcinoma. She was treated with anterior pelvic exenteration. The resected lymph nodes, vagina, uterine cervix, endometrium, ovaries, and urinary bladder were free of neoplasm. Histologically the neoplasm consisted of clear cells growing in sheets and occasional papillary structures. In some areas, hobnail cells were present. Ultrastructurally, the cells had apical caps, short microvilli, and complex cell bases, and contained abundant glycogen. These features were identified in one, but not the other of two previously reported cases. Because glycogen-rich clear cell carcinomas of the lower urinary tract do not resemble ultrastructurally mesonephric remnants or carcinomas known to arise from them, these glycogen-rich clear cell carcinomas should not be called “me-sonephromas” as has been the practice.     

Glycogen-rich Clear Cell Carcinoma of the Urethra: An Ultrastructural Study

A 49-year-old black woman developed a urethral glycogen-rich clear cell carcinoma. She was treated with anterior pelvic exenteration. The resected lymph nodes, vagina, uterine cervix, endometrium, ovaries, and urinary bladder were free of neoplasm. Histologically the neoplasm consisted of clear cells growing in sheets and occasional papillary structures. In some areas, hobnail cells were present. Ultrastructurally, the cells had apical caps, short microvilli, and complex cell bases, and contained abundant glycogen. These features were identified in one, but not the other of two previously reported cases. Because glycogen-rich clear cell carcinomas of the lower urinary tract do not resemble ultrastructurally mesonephric remnants or carcinomas known to arise from them, these glycogen-rich clear cell carcinomas should not be called “me-sonephromas” as has been the practice.     

Merkel Cell Carcinoma with Pagetoid Spread

A case of Merkel cell carcinoma showing epidermo-tropism is presented. The neoplastic cells displayed dotlike immunoreactivity for cytokeratins and strong immunoreactivity for neuron-specific eno-lase. Although no neuroendocrine granules were found, characteristic paranuclear fibrous bodies were present.     

Small Cell Neuroendocrine Carcinoma of the Urinary Bladder: Report of Three Cases with Ultrastructural Analysis

Three cases of small cell neuroendocrine carcinoma of the urinary bladder were studied by light and electron microscopic techniques. Dense-core, membrane-bound granules were identified in the cytoplasm of all 3 cases, substantiating the light microscopic impression of a morphologic similarity to other neuroendocrine carcinomas, such as small cell (oat cell) carcinoma of the lung. Two of the three cases showed clinical evidence of distant metastases, suggesting an aggressive biologic potential of this tumor similar to oat cell carcinoma of the lung. A partial remission was induced in these 2 cases using chemotherapy protocols similar to the drug regimens for small cell (oat cell) carcinomas of the lung. Recognition of this distinct entity has important clinical implications regarding therapeutic approach.     

Transplantable Acinar Cell Carcinoma of the Rat Pancreas: Morphologic and Biochemical Characterization

An acinar cell carcinoma of the pancreas, which developed in a F-344 rat after long-term nafenopin administration, was serially transplanted into inbred weanling rats by subcutaneous and intraperitoneal routes. The transplantability rate was 95% or more by both routes. The tumor implants became palpable in 20 to 30 days after subcutaneous transplantation, increasing in size rapidly thereafter during the next 25 to 30 days. In intraperitoneal recipients the abdomen was markedly distended within 1 month. No metastases were observed in this series of transplantations. Amylase and lipase levels in serum and tumor homogenates increased with tumor size. Morphologically, only a few cells contained zymogen granules immediately after the appearance of a palpable tumor; at later intervals, however, these granules were observed in many tumor cells. Seventy-two hours after the surgical removal of tumors, the serum amylase and lipase levels returned to control values. This transplantable pancreatic acinar cell carcinoma can be dissociated into functionally viable single cells by a simplified enzyme digestion and divalent cation chelation procedure. By light microscopic autoradiography, approximately 20% of these isolated cells were found to incorporate ³H-thymidine in vitro into nuclear DNA. The data presented in this paper should serve as a baseline for future studies on this transplanted tumor.     

Case for the Panel: Filamentous Bodies in a Squamous Cell Carcinoma

A primary hepatic gastrinoma found in a 13-year-old boy was studied by light microscopy, immunohistochemistry, electron microscopy, and immunoelectron microscopy. Results were consistent with a neuroendocrine neoplasm with abundant gastrin-immunoreactive cells. Unlike all previously reported cases of primary hepatic neuroendocrine tumors, which have been endocrinologically asymptomatic, the patient had a Zollinger-Ellison syndrome apparently cured by surgical resection of the tumor.     

原发性肝细胞癌胞核及核内包涵体的超微结构研究

通过光镜和电镜研究了人原发性肝细胞癌胞核及核内包涵体的形态改变、结构、性质和意义。光镜下肝癌胞核普遍增大、核膜增厚、核仁明显。电镜下胞核明显畸形,核内可见各种形态的假包涵体,检出率为73%,还可以见到其他包涵体。越是分化差的肝癌,核的改变越明显。核的改变情况可作为衡量肝癌分化程度的指标之一。     

Amphicrine Differentiation in Bronchioloalveolar Cell Carcinoma

We report for the first time a classical bronchioloalveolar cell carcinoma with both exocrine and endocrine differentiation (amphicrine) in the same cell. At electron microscopy the tumor cells showed a mixed type II alveolar cell/Clara cell and mucous differentiation. In addition, there were many dense-core neurosecretory granules at the base of the majority of the cells. Immunocytochemically the tumor showed positivity for surfactant and a panel of neuroendocrine antibodies, including NSE, PGP9.5, synaptophysin, and chromogranin A. The presence of neuroendocrine differentiation was not hinted at by routine histology and did not indicate a more aggressive behavior in this case since the patient is well 3 years after the resection.