Ultrastructural Characterization of Mammary Analogue Secretory Carcinoma of the Salivary Glands: A Distinct Entity from Acinic Cell Carcinoma?

Mammary analogue secretory carcinoma (MASC) of the salivary glands is a recently described neoplasm of the salivary glands with a characteristic morphology complemented by a specific cytogenetic translocation and gene rearrangements. Although immunophenotypic and cytogenetic differences allow for a more reliable distinction, ultrastructural features can also provide important information about the relationship between MASC, classic acinic cell carcinoma (AciCC), and AciCC intercalated duct cell-predominant variant. Following approval from the hospital's institutional review board, 7 cases of MASC, 8 cases of classic AciCC, and 4 cases of AciCC intercalated duct cell-predominant variant were retrieved from the pathology files of Massachusetts General Hospital from 2012 to 2015. Electron microscopy was performed using formalin-fixed, paraffin-embedded tissue. Ultrastructural features of all 19 neoplasms of the salivary glands were recorded. The predominant cell-types observed in MASC are those with intercalated/striated duct cell differentiation. These features include prominent invaginations of the cell surface studded with microvilli, and some intra- and intercellular lumina also with a microvillous surface. Classic AciCC dominant cell-type recapitulates acinar cell differentiation. These cells contain large intracytoplasmic zymogen-like granules. AciCC intercalated duct cell-predominant variant showed both cell populations in various proportions with the intercalated/striated duct cell type usually being the dominant one. MASC presents with distinctive ultrastructural features that allows its proper differentiation from classic AciCC. However, significant ultrastructural features overlaps between both AciCC intercalated duct cells-predominant and classic AciCC and MASC. These findings indicate a very close proximity between these tumors.

Combined DOG1 and Mammaglobin Immunohistochemistry Is Comparable to ETV6-breakapart Analysis for Differentiating Between Papillary Cystic Variants of Acinic Cell Carcinoma and Mammary Analogue Secretory Carcinoma.

BACKGROUND: We investigated the reliability of combined DOG1 and mammaglobin immunohistochemistry compared with ETV6 fluorescence in situ hybridization (FISH) in the assessment of salivary tumors previously diagnosed as acinic cell carcinoma (ACC). Ultrastructural features of cases reclassified as mammary analogue secretory carcinoma (MASC) were assessed by transmission electron microscopy (TEM). METHODS: Immunohistochemical (IHC) reactivity to DOG1 and mammaglobin was validated against FISH targeting the ETV6 gene in all 14 cases. RESULTS: Three cases with papillary cystic histomorphology previously diagnosed as ACC were revised to MASC. TEM features of the ETV6 rearrangement-positive MASC cases showed large numbers of secretory granules with extrusion into the intercellular spaces, well-developed endoplasmic reticulum, lipid-laden vacuoles, well-formed microvilli, and large lining cystic spaces. CONCLUSIONS: Combined DOG1 and mammaglobin immunohistochemistry is comparable to ETV6 -breakapart analysis for differentiating between papillary cystic variants of ACC and MASC.

Pancreatic-type Acinar Cell Carcinoma of the Stomach Included in Multiple Primary Carcinomas.

BACKGROUND/AIM: Pancreatic-type acinar cell carcinoma (ACC) in the stomach is extraordinarily rare. We pathologically examined two cases with multiple primary carcinomas, including gastric tumors. PATIENTS AND METHODS: Gastric cancer specimens were examined by immunostaining and electron microscopy. RESULTS: Both cases had cancer cells with acinar patterns, resembling pancreatic ACC. The cancer cells in the first case were positive for exocrine markers, including chymotrypsin, lipase and alpha-1 antichymotrypsin (ACT), as well as neuroendocrine markers, including chromogranin A and synaptophysin. The cancer cells in the second case were positive for chymotrypsin and alpha-1 ACT, while being slightly positive for chromogranin A and synaptophysin. Ultrastructurally, cancer cells contained zymogen granules in both cases. The final diagnosis was pancreatic mixed acinar-neuroendocrine carcinoma and pure pancreatic ACC, respectively. CONCLUSION: We confirmed two cases with gastric pancreatic-type ACC included in multiple primary carcinomas. This type of double cancer has not been reported previously.

Acinar cell carcinoma versus solid pseudopapillary tumor of the pancreas in children: a comparison of two rare and overlapping entities with review of the literature.

Primary epithelial tumors of the pancreas are extremely uncommon in children, and among these, acinar cell carcinoma (ACC) is the most rare. Here we describe our recent observations in the case of a 10-year-old boy with one of these exceptional examples. The histologic diagnosis of ACC was supported by both immunohistochemistry and electron microscopy. Despite its rarity, ACC should be kept in the differential diagnosis of pediatric pancreatic exocrine tumors. We also provide a comparison with an example of solid pseudopapillary tumor, another relatively infrequent epithelial tumor of the pancreas in the young. We review the relevant literature addressing the clinical and pathologic features of ACC and its distinction from other pancreatic neoplasms.

Fine-needle aspiration cytology of pancreatoblastoma in a young woman: report of a case and review of the literature.

Pancreatoblastoma is a rare tumor and has been reported only four times in the cytologic literature, three times in fine-needle aspiration (FNA) biopsy and once in an imprint of resected tumor. We are reporting the fourth case of FNA cytology with immunohistochemical and electron microscopic studies. The patient is a 24-yr-old African American woman, who presented with a pancreatic mass, hepatic masses, and abdominal lymphadenopathy. The aspiration smears of the liver mass showed a biphasic tumor composed of bland-appearing primitive spindled stromal fragments with "spider-web"-like long fibrils interconnecting with sharply angulated islands of cohesive epithelium. At high power, the epithelium is composed of medium-sized cells with round-to-oval vesicular nuclei with fine chromatin and one-to-two small nucleoli. The neuroendocrine component was demonstrated immunohistochemically with synaptophysin and chromogranin expressions. The acinar component and squamoid component were demonstrated ultrastructurally by the presence of 400-600 nm zymogen granules and tonofilaments. The literature was reviewed and the cytological features of all the four cases of pancreatoblastoma are summarized.

Sinonasal acinic cell carcinoma: a clinicopathologic study of four cases.

BACKGROUND: Acinic cell carcinoma is a low-grade malignant epithelial salivary gland neoplasm with a predilection for the parotid gland. To date, only 11 cases of sinonasal acinic cell carcinomas have been reported in the English-language literature. We present the clinicopathologic features of four sinonasal acinic cell carcinomas. METHODS: The demographic data and pathologic material of four patients with sinonasal acinic cell carcinoma identified from the files of the Department of Pathology at The University of Texas M. D. Anderson Cancer Center between 1984 and 2002 were reviewed. RESULTS: The four patients were two men and two women, with an age range of 42 to 65 years (mean, 54 years). The patients were initially seen with unilateral nasal obstruction. Histologically, all tumors were composed of round to ovoid cells with clear and/or basophilic granular cytoplasm and round, hyperchromatic, small, eccentrically located nuclei. The growth pattern was lobular, solid, and follicular. Histochemically, periodic acid-Schiff diastase-resistant granules were demonstrated in all cases. All patients were treated surgically. In addition, one patient received postoperative radiation. All patients are alive and well, with follow-up from 4 to 17 years. CONCLUSIONS: Sinonasal acinic cell carcinoma is a distinct low-grade carcinoma that can be distinguished from other neoplasms by light microscopy and histochemical staining methods. Pathologists and surgeons should be aware of the occurrence of this type of salivary gland neoplasm in the sinonasal tract.

Pancreatic acinar cell carcinoma with endocrine differentiation: immunohistochemical and ultrastructural analyses.

The majority of pancreatic malignant tumors are adenocarcinomas of the ductal type (ductal cell carcinomas) and combined tumors consisting of different tumor components are very rare. We present here a rare case of acinar cell carcinoma with apparent foci of endocrine differentiation. A 46-year-old man underwent pylorus-preserving pancreatoduodenectomy under the diagnosis of pancreatic tumor. The pancreatic tumor was mainly composed of typical acinar cell carcinoma, but some tumor cells were positive for both acinar and endocrine cell markers such as pancreatic amylase, trypsin, lipase and chromogranin A. At the electron-microscopic level, the tumor cells were seen to have numerous electron-dense neuroendocrine, as well as a few zymogen-like, granules. The tumor part positive for both acinar and endocrine cell markers originated from a subclone (dis-differentiated tumor cells) of the typical acinar cell carcinoma tissue of the pancreas.

Immunohistochemistry in the differential diagnosis of acinar and endocrine pancreatic neoplasms.

Histologic differential diagnosis of acinar cell carcinoma (ACC), mixed acinar-endocrine cell carcinoma (MAEC), and pancreatic endocrine tumors (PET) can be difficult but is important because of differences in their clinical behavior. This study investigates the utility of immunohistochemistry (IHC) in this differential diagnosis using immunohistochemical stains that are available in most laboratories. IHC was performed on paraffin-embedded tissue in ACC (n = 6), MAEC (n = 2), and PET (n = 13), using synaptophysin (SYN), chromogranin (CHR), chymotrypsin (CHY), and alpha-1-antitrypsin (AAT). Electron microscopy (EM) was performed in all cases to confirm the diagnosis. Long-term follow-up and death of disease (DOD) was known in all patients. The ACCs stained as follows: CHY (4/6), AAT (3/6), SYN (4/6); CHR was negative in all cases. Both cases of MAEC stained with CHY, AAT, and SYN (2/2); CHR was negative. PET stained as follows: SYN (13/13), CHR (8/13), CHY (4/13), AAT (5/13). In the ACC/ MAEC group, six of eight patients were DOD at mean follow-up of 11 months. Among the PET, two of 16 patients were DOD at mean follow-up of 37 months. Considerable immunophenotypic overlap exists between ACC, MAEC, and PET. Consequently, one can neither confirm nor rule out a diagnosis of ACC or MAEC using generally available immunohistochemical stains alone. These findings support a role for EM in the evaluation of exocrine and endocrine pancreatic neoplasms.

Acinar cell carcinoma of the pancreas showing finger-print-like zymogen granules by electron microscopy: immunohistochemical study.

A rare case of finger-print-like zymogen granules shown by electron microscopy is reported. The patient was a 75-year-old man who was histologically and ultrastructurally confirmed to have acinar cell carcinoma of the pancreas. Frozen section and postmortem examination revealed that the tumor was made up of solid nests of cells resembling the appearance of normal pancreatic acini, showing polygonal cells which had round or oval nuclei, and rare mitotic figures. Zymogen-like granules, shown by eosinophilic granular staining, were abundant in the cytoplasm. Electron microscopy showed that the tumor cells were closely packed, occasionally forming small intercellular spaces resembling pancreatic acini (microtubules). The cytoplasm contained characteristic zymogen granules with dark-to-medium electron density, measuring 660 nm +/-213 SD in diameter. The granules of medium density were large, and showed finger-print-like patterns. Investigation of more cases is necessary to identify whether these finger-print-like patterns are an important factor in the genesis of acinar cell carcinoma.

Acinar-islet cell tumor of the pancreas: report of a malignant pancreatic composite tumor.

An unusual case of malignant pancreatic composite tumor with both components of acinar cell tumor (ACT) and islet cell tumor (ICT) was investigated histologically, immunohistochemically, and ultrastructurally. The pancreatic tumor with central cyst formation was found on computerized tomographic examination of a 72-year-old man reporting appetite and weight loss. The ACT component was present in the original pancreatic region and the ICT region was adjacent to the ACT. ACT was immunohistochemically positive for pancreatic amylase, whereas ICT had argyrophil tumor cells immunohistochemically positive for chromogranin A. There were several tumor cell nests positive for both pancreatic amylase (acinar differentiation) and chromogranin A (islet differentiation). We speculated that ICT may have arisen from the de-differentiated tumor cells in the ACT after the occurrence of ACT.

Unusual prostatic adenocarcinoma with endocrine basophilic FSH-immunoreactive cells.

We report an unusual variant of prostatic adenocarcinoma with marked endocrine differentiation (mixed endocrine-exocrine adenocarcinoma). Endocrine cells accounted for 60% of the tumour cells, were positive with silver impregnation and for chromogranin A, synaptophysin, and neuron-specific enolase, and coexpressed the exocrine antigens prostatic acid phosphatase and prostatic-specific antigen. Most of the endocrine cells were basophilic with haematoxylin-eosin and proved immunoreactive for alpha subunit of human chorionic gonadotropin and follicle-stimulating hormone. The remaining endocrine cells were represented by eosinophilic cells positive for serotonin, and by calcitonin and serotonin-immunoreactive cells not identifiable in haematoxylin-eosin-stained sections. On ultrastructural analysis, two types of endocrine cells were identified. The most frequent cell type showed abundant cytoplasmic round, electron-dense neurosecretory granules, either small (212+/-44 nm) or large (471+/-114 nm), resembling those of gonadotropic pituitary cells. The second type of endocrine cells contained irregular electron-dense granules similar to those of serotonin-storing enterochromaffin cells.

Acinic cell carcinoma of the breast: an immunohistochemical and ultrastructural study.

The clinicopathological features of six cases of breast carcinomas showing features of acinic cell differentiation, which are similar to those seen in homologous tumors of salivary glands, are presented. The patients, all women, were 35-80 years of age. One case recurred after 4 years, and in two cases axillary lymph node metastases were found at the time of surgery. Histologically the tumors showed a microglandular pattern merging with solid areas. Cytologically, immunohistochemically, and ultrastructurally the tumors were very similar to cases of acinic cell carcinoma of the parotid gland. The differential diagnostic criteria with microglandular adenosis and carcinomas showing granular cytoplasm are discussed. It seems that acinic cell carcinomas of the breast have to be added to the long list of tumors that affect the salivary glands and can also arise in the breast.

Ultrastructural study of intranuclear inclusion bodies of pulmonary adenocarcinoma.

Intranuclear inclusion bodies are sometimes observed in pulmonary adenocarcinoma by light microscopy. Electron microscopic characteristics of lung cancer cells with intranuclear inclusion bodies were studied. In addition, polymerase chain reaction (PCR) was performed using primers coding for human papillomavirus (HPV) types 16, 18, and 33. Eosinophilic intranuclear inclusion bodies were observed in 22 out of 285 cases by light microscopy. Immunohistochemically, cancer cell nuclei stained with PE-10. Three types of intranuclear inclusion bodies were classified electron microscopically. Type A showed aggregation of electron dense particles (30-40 nm) with an electron-dense core and was most frequently observed. Type B consisted of a mass of branching and whirling tubular structures. Type B intranuclear inclusions had a relationship with inner nuclear membrane. In type C, several spherical inclusions were observed in one nucleus. HPV DNA was detected using PCR and type-specific probes in a case with type A inclusion bodies. This study suggests that intranuclear inclusion bodies in pulmonary adenocarcinoma are formed by several different mechanisms.

[Giant acinic cell parotid gland adenocarcinoma of the papillary- cystic type]. / Adenocarcinoma gigante de células acinares de tipo quístico papilar en parótida.

A case of a 38-year-old male having an acinic cell adenocarcinoma of the parotid gland is reported. The tumor measured 22 cm and histologically it was of the papillary-cystic type. The following features were of interest: 1) the tumor size surpassed the size of previous reported acinic cell adenocarcinomas by 9 cm; and 2) the rarity of its histological variety (cystic papillary) demanded immunohistochemical and electron microscopic studies to confirm the diagnosis.

Adenocarcinoma gigante de células acinares de tipo quístico papilar en parótida / Giant acinic cell adenocarcinoma with papillary-cystic pattern of the parotid gland

Se presenta el caso de un hombre de 38 años de edad con un adenocarcinoma de células acinares de 22 cm de tipo quístico papilar, originado en la glándula parótida. El interés del caso radica en: 1) el tamaño del tumor que supera en 9 cm al adenocarcinoma de células acinares más grande hasta ahora informado; y 2) la rara variedad histológica quística y papilar demandó estudios de histoquímica, inmunohistoquímica y microscopía electrónica para su diagnóstico