Yueh-Hung Chou

Papillary-cystic pattern is characteristic in mammary analogue secretory carcinomas but is rarely observed in acinic cell carcinomas of the salivary gland

Mammary analogue secretory carcinoma (MASC) has a specific ETV6-NTRK3 translocation and morphologically overlaps with acinic cell carcinoma (AciCC). Before the recognition of MASC, in AciCC, four histologic patterns were identified including microcystic, solid, papillary-cystic, and follicular. The aim of this study was to evaluate histologic patterns in these two neoplasms through comprehensive histologic subtyping. Using fluorescence in situ hybridization (FISH), we identified 14 cases of MASC and 21 cases of AciCC. We used comprehensive histologic subtyping to provide a semiquantitive assessment of histologic patterns in each tumor and performed immunohistochemical analyses including S100/vimentin/mammaglobin/DOG1. MASC often presented papillary-cystic patterns without a solid component, previously considered to be one of the four major patterns associated with AciCC. However, in our study, this histologic feature was rarely seen in AciCC and more characteristic of MASC. In aspiration cytology samples, MASC was associated with more cellular atypia. An immunohistochemical panel of S100/mammaglobin/DOG1 was found useful for differential diagnosis. Comprehensive subtyping of histologic patterns is a useful screening method prior to initiation of molecular testing.

Colonic necrosis in a young patient receiving oral kayexalate in sorbitol: Case report and literature review

Kayexalate (sodium polystyrene sulfonate) is a cation‐exchange resin used to treat patients with hyperkalemia. Concomitant administration of kayexalate and sorbitol may induce gastrointestinal injury, which is potentially lethal. However, this well‐documented complication is often underrecognized both clinically and pathologically. We propose a typical case along with colonoscopic photos and microscopic pictures. Additionally, we also present a review of the literature on this rare drug‐induced side effect.

Carbonic anhydrase VI: a novel marker for salivary serous acinar differentiation and its application to discriminate acinic cell carcinoma from mammary analogue secretory carcinoma of the salivary gland

Carbonic anhydrase VI (CA6) is present in serous acinar cells of human salivary glands. The aim of this study was to investigate the diagnostic utility of CA6 in differentiating acinic cell carcinoma (AciCC) from its morphological mimic mammary analogue secretory carcinoma (MASC) of the salivary gland.

Histologic Evolution From Adenocarcinoma to Squamous Cell Carcinoma After Gefitinib Treatment

We report two cases of lung cancer with histologic transformation from adenocarcinoma to squamous cell carcinoma after gefitinib treatment. Both cases involved advanced lung cancers, initially confirmed as adenocarcinomas with sensitive epidermal growth factor gene mutations. After gefitinib treatment, the second pathologic examination in each case revealed squamous cell carcinoma retaining identical mutations without newly acquired resistance mutations. The underlying mechanism may have been pluripotent tumor cells with divergent differentiation or mixed lung cancer including both adenocarcinomatous and squamous cell carcinomatous components. This report widens the spectrum of histologic evolution as a mechanism underlying the acquisition of drug resistance.

Metastasizing Ameloblastoma With Localized Interstitial Spread in the Lung Report of Two Cases

Ameloblastoma is a locally aggressive, epithelial odontogenic tumor involving mandibles and maxillas. Distant metastasis is a very rare condition and is designated as metastasizing (malignant) ameloblastoma despite its benign histological appearance. Up to now, only 27 well-documented cases of metastasizing ameloblastomas are reported in the literature, and lung is the most commonly involved organ. In previous reports of pulmonary metastasizing ameloblastomas, there was little description of the histopathologic finding. Here, the authors report 2 cases of pulmonary metastasizing ameloblastomas with special emphasis on their interesting, interstitial spread along alveolar septa, resulting in a unique 2-cell pattern under microscopic examination. Pulmonary metastasizing ameloblastoma may pose difficulty in diagnosis if the pathologist is not aware of patient’s clinical history of ameloblastoma.

Intravascular Large B Cell Lymphoma in Taiwan: An Asian Variant of Non-germinal-center Origin

BACKGROUND/PURPOSE Intravascular large B cell lymphoma (IVLBCL) is a rare variant of diffuse large B cell lymphoma. We reported the clinical and immunohistochemical characteristics of 10 cases of IVLBCL from Taiwan between 1995 and 2008. METHODS Clinical data were reviewed and immunoperoxidase stains were performed with antibodies against CD20, CD10, Bcl-6, MUM1, and CD5. RESULTS There were eight males and two females with a median age of 59 years. Patients presented with dyspnea (5/10), fever (7/10), splenomegaly (5/10), and bone marrow involvement (8/10). Anemia (9/10), thrombocytopenia (6/10), and elevated serum lactate dehydrogenase or ferritin levels (8/10) were also common. Nine cases were CD20+CD10(-)Bcl-6(-), similar to non-germinal center B cells. Six out of seven patients survived after chemotherapy, but three cases with thrombocytopenia that precluded chemotherapy died within 2 months. CONCLUSION Our cases of IVLBCL had a non-germinal center B origin and belonged to the Asian variant of this disease. The liver, spleen, and bone marrow, but rarely the skin or brain, were involved. Thrombocytopenia is a major risk factor for mortality in these cases.

Mixed Lung Mucoepidermoid Carcinoma and Adenocarcinoma With Identical Mutations in an Epidermal Growth Factor Receptor Gene

Lung cancers presenting two different histologic types are relatively rare. This paper presents a case report of mixed lung cancer comprising mucoepidermoid carcinoma and conventional adenocarcinoma, a combination that has not been reported previously. These two carcinomas showed distinct morphologic and immunohistochemical features. However, gene analysis revealed identical mutations in each component, which indicates they possess a monoclonal origin. Specifically, we identified the same mutation in exon 19 of the epidermal growth factor receptor gene. Molecular analysis further substantiated a monoclonal origin with divergent differentiation, as opposed to the collision of discrete tumors.

Water-clear cell parathyroid adenoma in a patient with acute pancreatitis.

Department of Pathology, National Taiwan University Hospital, Taipei, TaiwanReceived 11 October 2012; received in revised form 16 October 2012; accepted 19 October 2012Water-clear cell parathyroid adenoma is a very rare histo-logical variant of parathyroid adenoma and is exclusivelycomposed of water-clear cells that are characterized byabundant clear cytoplasm. This variant was first reported in1994 and currently only 12 cases were reported in litera-ture.

Endocrine mucin-producing sweat gland carcinoma with GATA3 expression: report of two cases.

Sir, Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare, low-grade cutaneous adnexal carcinoma with neuroendocrine differentiation and may be a precursor lesion of mucinous carcinoma of the skin (MCS). The tumour typically affects the eyelids of elderly women and is morphologically analogous to endocrine ductal carcinoma in situ (eDCIS)/solid papillary carcinoma (SPC) of the breast. Given the overlapping histological and immunohistochemical features, differentiating EMPSGC from cutaneous metastasis of a breast cancer is important but often difficult. GATA binding protein 3 (GATA3) is a transcription factor that has recently been identified as a useful immunohistochemical marker highly expressed in urothelial and breast carcinomas. However, GATA3 expression in EMPSGC is rarely discussed and not well understood. Here, we present two cases of GATA3 positive EMPSGC (including the first documented male case) and review the relevant literature. The first case was an 87-year-old man presenting with a 7 mm painless solitary nodule on his left cheek (Fig. 1A), slowly growing over the course of 1 year. The patient did not have clinical evidence of a breast carcinoma or other visceral malignancy. Excisional biopsy was performed under the impression of hidradenoma. Histopathological examination showed a multinodular dermal tumour with solid and cribriform patterns (Fig. 1B). Under high power, the lesion was composed of polygonal cells with monomorphic nuclei, finely stippled chromatin and abundant eosinophilic cytoplasm (Fig. 1C). The tumour border was focally infiltrative with extravasated mucin pools (Fig. 1D). Immunohistochemically, the tumour was positive for oestrogen receptor (ER) (Fig. 1E), progesterone receptor (PR), GATA3 (Fig. 1F), Wilms tumour 1 (WT1) and synaptophysin (Fig. 1G). p63 immunostain demonstrated a preserved myoepithelial layer around non-invasive dermal nodules and was lost in infiltrative areas (Fig. 1H). Mucicarmine stain highlighted intracellular and extracellular mucin (Fig. 1I). An EMPSGC with associated mucinous carcinoma was diagnosed. Subsequent panendoscopy, colonoscopy and ultrasound examination of the breast and abdomen were normal. Since the surgical margin from the first excision was positive, a re-excision was performed to achieve clear margins (greater than 5 mm). No recurrence was noted after 10 months. The second case was a 55-year-old woman without underlying diseases, who presented with a 2 mm papule on the left upper eyelid for 3 months. A surgical procedure was performed for cosmetic reasons. Histopathological examination revealed a well-circumscribed dermal tumour composed of uniform cells with abundant cytoplasm. Solid and cribriform arrangements were noted and mucin production was evident (Fig. 2A). A frank invasive component was not identified. Immunohistochemically, the tumour was positive for ER (Fig. 2B), PR, GATA3 (Fig. 2C) and synaptophysin (Fig. 2D). However, the lesion disappeared in

Epithelial-Myoepithelial Carcinoma of the Salivary Gland Harboring HRAS Codon 61 Mutations With Lung Metastasis.

Here, we report a case involving a 43-year-old man diagnosed with Burkitt lymphoma in 2007. At the same time, 2 small lung nodules were incidentally found; however, they presented no indication of growth throughout the follow-up period. However, a 1.5-cm nodule located in the right parotid gland in 2010 gradually increased in size to 2.8 cm by 2012. A parotidectomy revealed an epithelial-myoepithelial carcinoma, characterized by biphasic tubular structures and solid areas presenting myoepithelial overgrowth. Tumor necrosis and regional lymph node invasion were also observed. During clinical follow-up in 2013, a new 1.3-cm nodule was identified in the left lower lobe of the lung, which enlarged to 3 cm by 2014. Wedge resection of the left lung nodules revealed round nodes with well-defined borders. Histologically, these lung tumors predominantly comprised spindle-shaped myoepithelial cells with occasional tubular structures. Numerous cleft-like spaces lined by entrapped TTF-1-immunoreactive pneumocytes were observed inside the nodules. The lung nodules were characterized by a morphology similar to that of the parotid cancer. Epithelial-myoepithelial carcinoma with lung metastasis was confirmed by molecular testing, which revealed identical HRAS codon 61 (Q61K) mutations in the primary parotid tumor as well as in the lung metastases.