Coexpression of c-kit and bcl-2 in Small Cell Carcinoma and Large Cell Neuroendocrine Carcinoma of the Lung

Olfactory neuroblastoma in a domestic cat and review of the literature

Nasal tumors account for less than 10% of all feline neoplasms, with lymphoma, followed by adenocarcinoma, and squamous cell carcinoma, the most commonly reported. Nasal neuroectodermal tumors, including olfactory neuroblastoma (ONB), are scarcely described, and their tumorigenesis is largely unknown. Here we report the cytological, histological, and immunohistochemical features of a feline ONB. We also provide a pathological review of nasal neuroendocrine neoplasms in cats. A 7-year-old Burmese cat was evaluated for sneezing, occasional epistaxis, and upper respiratory noise for 8 months. Computed tomography (CT) imaging revealed a 7 × 5 × 3 mm irregular mass effacing and expanding the nasal cavity, which extended to the nasopharynx. Cytologically, neoplastic cells were round to polygonal and had a round nucleus with finely stippled chromatin, a single small nucleolus, and abundant pale blue cytoplasm, which contained abundant fine pale pink granules. They exhibited mild cellular atypia, anisocytosis, and mild to occasionally moderate anisokaryosis. Rhinoscopic biopsies revealed a densely cellular, malignant neuroepithelial neoplasm. Cells were arranged in densely packed trabeculae and formed Homer Wright and Flexner-Wintersteiner-like rosettes, with rare mitotic figures and scant supportive fibrovascular stroma. Immunohistochemically, neoplastic cells were positive for vimentin, cytokeratin AE1/AE3, COX-2, and beta-tubulin and negative for S-100, chromogranin A, CD117, and epithelial membrane antigen (EMA). An ONB was diagnosed based on histological and immunohistochemical findings. Interestingly, and similar to nasal carcinomas, neoplastic cells diffusely neo-expressed COX-2. To the authors' knowledge, there is no previous evidence of COX-2 in feline ONB. Histopathology and immunohistochemistry are required for a definitive diagnosis of ONB.

Concurrent occurrence of adenoid cystic carcinoma of the salivary glands with small cell carcinoma of the liver: A rare case report

Adenoid cystic carcinoma (ACC) is a clinically deceptive and histologically specific malignancy of salivary gland origin. It is the most common minor salivary gland malignancy. Small cell carcinoma (SCC) is a type of undifferentiated malignant neuroendocrine tumor reported rarely in the liver. Though there are many reported cases of SCC involving liver and ACC of minor salivary glands, the review of literature does not show any reports of concomitant occurrence of these two tumors. We describe a rare case of ACC of the oral cavity and its coexistence with a SCC involving liver, identified and confirmed by histological, and immunohistochemical observations. To our knowledge, this is the first reported case of an ACC of the oral cavity and SCC of liver occurring concomitantly in the same patient.

Small cell neuroendocrine carcinoma of the prostate: incidence and a report of four cases with an examination of KIT and PDGFRA

Because there have been no reports on the incidence and expressions and mutations of KIT and PDGFRA in small cell neuroendocrine carcinoma (SCNEC) of the prostate, the author surveyed archival specimens of 2,642 prostatic specimens (biopsy, 1,503 cases; transurethral resection, 1,009 cases; prostatectomy, 130 cases). Of these, 706 cases were malignant tumors. In equivocal cases (n = 16) of Gleason 5 adenocarcinoma resembling SCNEC, several neuroendocrine markers were immunohistochemically examined. As the results, four cases of SCNEC were identified; therefore the incidence of SCNEC was 0.5% of all prostatic malignancies. All the four cases were biopsies. The remaining 686 cases were adenocarcinomas. In case 1 (50 years of age), the SCNEC tumor cells were positive for cytokeratin, P504S, synaptophysin, KIT, and PDGFRA, but negative for PSA, neuron specific enolase, CD56, and TTF-1. In case 2 (70 years of age), the tumor cells were positive for cytokeratin, PSA, P504S, chromogranin, and synaptophysin, but negative for neuron-specific enolase, CD56, TTF-1, KIT, and PDGFRA. In case 3 (72 years of age), the SCNEC tumor cells were positive for cytokeratin, PSA, P504S, synaptophysin, CD56, KIT, and PDGFRA, but negative for neuron-specific enolase, chromogranin, and TTF-1. In case 4 (81 years of age), the SCNEC tumor cell were positive for cytokeratin, PSA, P504S, chromogranin, synaptophysin, neuron-specific enolase, KIT, and PDGFRA, but negative for CD56 and TTF-1. A molecular genetic analysis using PCR-direct sequencing showed no mutations of KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) genes in three informative cases of SCNEC. The present cases were the first of prostatic SCNEC with an examination of KIT and PDGFRA expression and KIT and PDFGRA gene mutations.

Molecular and cellular biology of neuroendocrine lung tumors: evidence for separate biological entities

Pulmonary neuroendocrine tumors (NETs) are traditionally described as comprising a spectrum of neoplasms, ranging from low grade typical carcinoids (TCs) via the intermediate grade atypical carcinoids (ACs) to the highly malignant small cell lung cancers (SCLCs) and large cell neuroendocrine carcinomas (LCNECs). Recent data, however, suggests that two categories can be distinguished on basis of molecular and clinical data, i.e. the high grade neuroendocrine (NE) carcinomas and the carcinoid tumors. Bronchial carcinoids and SCLCs may originate from the same pulmonary NE precursor cells, but a precursor lesion has only been observed in association with carcinoids, termed diffuse idiopathic pulmonary neuroendocrine cell hyperplasia. The occurrence of mixed tumors exclusively comprising high grade NE carcinomas also supports a different carcinogenesis for these two groups. Histopathologically, high grade NE lung tumors are characterized by high mitotic and proliferative indices, while carcinoids are defined by maximally 10 mitoses per 2mm(2) (10 high-power fields) and rarely have Ki67-proliferative indices over 10%. High grade NE carcinomas are chemosensitive tumors, although they usually relapse. Surgery is often not an option due to extensive disease at presentation and early metastasis, especially in SCLC. Conversely, carcinoids are often insensitive to chemo- and radiation therapy, but cure can usually be achieved by surgery. A meta-analysis of comparative genomic hybridization studies performed for this review, as well as gene expression profiling data indicates separate clustering of carcinoids and carcinomas. Chromosomal aberrations are much more frequent in carcinomas, except for deletion of 11q, which is involved in the whole spectrum of NE lung tumors. Deletions of chromosome 3p are rare in carcinoids but are a hallmark of the high grade pulmonary NE carcinomas. On the contrary, mutations of the multiple endocrine neoplasia type 1 (MEN1) gene are restricted to carcinoid tumors. Many of the differences between carcinoids and high grade lung NETs can be ascribed to tobacco consumption, which is strongly linked to the occurrence of high grade NE carcinomas. Smoking causes p53 mutations, very frequently present in SCLCs and LCNECs, but rarely in carcinoids. It further results in other early genetic events in SCLCs and LCNECs, such as 3p and 17p deletions. Smoking induces downregulation of E-cadherin and associated epithelial to mesenchymal transition. Also, high grade lung NETs display higher frequencies of aberrations of the Rb pathway, and of the intrinsic and extrinsic apoptotic routes. Carcinoid biology on the other hand is not depending on cigarette smoke intake but rather characterized by aberrations of other specific genetic events, probably including Menin or its targets and interaction partners. This results in a gradual evolution, most likely from proliferating pulmonary NE cells via hyperplasia and tumorlets towards classical carcinoid tumors. We conclude that carcinoids and high grade NE lung carcinomas are separate biological entities and do not comprise one spectrum of pulmonary NETs. This implies the need to reconsider both diagnostic as well as therapeutic approaches for these different groups of malignancies.

Esophageal combined carcinomas: Immunohoistochemical and molecular genetic studies

Primary esophageal combined carcinoma is very rare. The authors herein report 2 cases. Case 1 was a combined squamous cell carcinoma and small cell carcinoma, and case 2 was a combined squamous cell carcinoma, adenocarcinoma, and small cell carcinoma. Case 1 was a 67-year-old man with complaints of dysphagia. Endoscopic examination revealed an ulcerated tumor in the middle esophagus, and 6 biopsies were obtained. All 6 biopsies revealed a mixture of squamous cell carcinoma and small cell carcinoma. Both elements were positive for cytokeratin, epithelial membrane antigen, and p53 protein, and had high Ki-67 labeling. The small cell carcinoma element was positive for synaptophysin, CD56, KIT, and platelet-derived growth factor-α (PDGFRA), while the squamous cell carcinoma element was not. Genetically, no mutations of KIT and PDGFRA were recognized. The patient died of systemic carcinomatosis 15 mo after presentation. Case 2 was a 74-year-old man presenting with dysplasia. Endoscopy revealed a polypoid tumor in the distal esophagus. Seven biopsies were taken, and 6 showed a mixture of squamous cell carcinoma, small cell carcinoma, and adenocarcinoma. The 3 elements were positive for cytokeratins, epithelial membrane antigen, and p53 protein, and had high Ki-67 labeling. The adenocarcinoma element was positive for mucins. The small cell carcinoma element was positive for CD56, synaptophysin, KIT, and PDGFRA, but the other elements were not. Mutations of KIT and PDGFRA were not recognized. The patient died of systemic carcinomatosis 7 mo after presentation. These combined carcinomas may arise from enterochromaffin cells or totipotential stem cell in the esophagus or transdifferentiation of one element to another. A review of the literature was performed.

Large cell carcinoma of the lung: an endangered species?

This study aims to evaluate large cell carcinomas (LCC) of the lung with a panel of immunohistochemical markers in an attempt to identify tumors belonging to other categories. We analyzed a tissue microarray platform of 101 LCC with a panel of 31 monoclonal antibodies. The tumors were 82 (81.3%) classic LCC, 7 (6.9%) neuroendocrine LCC, 6 (5.9%) lymphoepithelioma-like LCC, 3 (2.9%) basaloid LCC, 2 (2%) clear cell LCC, and 1 (1%) LCC with rhabdoid phenotype. Characteristic classic LCC immunophenotype was loss of staining with CK5/6, CK14 positive in most squamous cell carcinoma (SCC), lack of MOC 31 positive in most adenocarcinomas, and positive immunoreactivity to EGFR, PDGFR-alpha and c-kit. 27 of 82 classic LCC (32.9%) were re-classified as adenocarcinomas, because they coexpressed TTF-1, CK7, and CK19, and were negative for p63. 31 (37.8%) of 82 classic LCC were reclassified as poorly differentiated SCC, based on their immunoreactivity with 34betaE12, p63, thrombomodulin, and CD44v6. 16 (19.5%) of 82 classic LCC correspond to undifferentiated adenosquamous carcinomas, since they displayed conflicting immunostaining for markers of both SCC and adenocarcinomas. The use of 7 immunohistochemical markers, consisting of TTF-1, CK7, CK19, p63, 34betaE12, thrombomodulin, and CD44v6, markedly reduces dramatically to less than 10%, the number of classic LCC by readily identifying cases of poorly differentiated SCCs, adenosquamous carcinoma and adenocarcinomas.

Large cell neuroendocrine carcinoma with sarcomatous changes of the endometrium: a case report with immunohistochemical studies and molecular genetic study of KIT and PDGFRA

The author herein reports a very rare case of large cell neuroendocrine carcinoma (LCNEC) with sarcomatous changes of the endometrium. A 40-year-old woman was admitted to our hospital because of abnormal uterine bleeding. Gynecologic examination and imaging modalities revealed a polypoid tumor of the uterine corpus. Uterine curettage biopsy revealed a sarcomatous undifferentiated carcinoma. Simple hysterectomy, salpingo-oophorectomy, extensive lymph node dissection, and omentectomy were performed. The patient was diagnosed as having FIGO stage Ib (T1N0M0) carcinoma, and adjuvant chemotherapy was performed. The patient is now alive 16 months after the operation. Pathologically, a polypoid tumor measuring 3x2x2 cm(3) was found in the uterine corpus. Histologically, the tumor consisted of relatively large-sized carcinoma cells without differentiation. The tumor cells have abundant cytoplasm and prominent nucleoli. It was composed of a spindle cell component (40%) and an epithelioid component (60%). A gradual transition between the two was recognized. Immunohistochemically, both elements showed the same immunophenotypes. The carcinoma cells were positive for cytokeratin, vimentin, CA125, CD34, estrogen receptor, progesterone receptor, p53 protein, Ki-67 antigen (80%), synaptophysin, CD56, KIT, and PDGFRA. They were negative for epithelial membrane antigen, CEA, desmin, S100 protein, melanosome, alpha-smooth muscle actin, chromogranin, and neuron-specific enolase. A molecular genetic analysis revealed no mutations of KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) genes. The final diagnosis was LCNEC with sarcomatous changes.

KIT-positive primary small cell carcinoma of the endometrium: a case report with immunohistochemical and molecular genetic analysis of KIT and PDGFRA genes

BACKGROUND

Primary small cell carcinoma of the endometrium is very rare, and there have been no reports on KIT and PDGFRA in endometrial small cell carcinoma.

CASE REPORT

An 87-year-old woman was admitted to our hospital because of genital bleeding. Endometrial cytology and biopsy revealed small cell carcinoma. Scrutiny of the body showed stage III endometrial carcinoma with metastases. An immunohistochemical study of the biopsy specimens revealed positive reactions for synaptophysin, CD56, KIT, and PDGFRA, and negative reactions for cytokeratins, neuron-specific enolase, and chromogranin. A molecular genetic analysis using PCR-direct sequencing identified no mutations of KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) genes. The patient received chemotherapy and radiation, but showed a downhill course, and died of carcinomatosis 6 months after the initial presentation.

CONCLUSION

The present case is the first reported case of primary small cell carcinoma of the endometrium with an examination of KIT and PDGFRA expressions and KIT and PDFGRA gene mutations.

Primary small cell carcinoma of the pleura: a case report with immunohistochemical and molecular genetic analyses of KIT and PDGFRA genes

An extremely rare case of primary small cell carcinoma of the pleura with an emphasis on KIT and platelet-derived growth factor receptor-α (PDGFRA) genes is reported here. A 67-year-old man underwent left testicular orchiectomy because of a testicular tumor. The tumor was immunohistochemically shown to be diffuse large B-cell lymphoma. The patient was treated with chemotherapy and radiation and followed up in our hospital. Eight years after the orchiectomy, the patient (75 years old) developed left pleural tumor and pleural effusion, and a biopsy was performed. The biopsy revealed a medullary malignant tumor consisting of small round and spindle cells. The following three possibilities were considered: recurrent lymphoma, mesothelioma, and small cell carcinoma. Immunohistochemically, the tumor cells were positive for cytokeratin, synaptophysin, CD56, KIT, and PDGFRA, but negative for CEA, cytokeratin 5/6, neuron-specific enolase, chromogranin, CD45, CD3, CD20, CD45RO, CD15, CD30, calretinin, WT-1, B72.3, D2-40, and TTF-1. Therefore, a diagnosis of pleural small cell carcinoma was made. A molecular genetic analysis using PCR-direct sequencing identified no mutations of KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) genes. The patient was treated with chemotherapy (cisplatin) and radiation (50 Gray). The present case is the first reported case of primary small cell carcinoma of the pleura with an examination of KIT and PDGFRA expressions and KIT and PDGFRA gene mutations.

High-grade neuroendocrine carcinoma of the lung: comparative clinicopathological study of large cell neuroendocrine carcinoma and small cell lung carcinoma

Large cell neuroendocrine carcinoma (LCNEC) and small cell lung carcinoma (SCLC) are high-grade neuroendocrine carcinomas. In order to clarify the similarities and differences between these cancers, 22 cases each of LCNEC and SCLC were collected and a comparative pathological study was carried out. First, their clinicopathological characteristics were confirmed, which were very similar to those previously reported. The 5 year survival rate of LCNEC and SCLC patients was 38.3% and 29.7%, respectively. The morphological characteristics of LCNEC and SCLC were then reviewed with regard to the morphology previously used to differentiate these cancers. As a result, many morphological indicators, such as tumor cell size, nuclear/cytoplasmic ratio, nuclear molding, rosette formation, prominent nucleoli and karyolysis were confirmed to be significant indicators for distinguishing LCNEC from SCLC. On comparative immunohistochemistry, LCNEC had significantly high staining scores for the expression of keratin 7 and 18, E- and P-cadherins, beta-catenin, villin 1, retinoblastoma protein (pRB), c-met and alpha-enolase. These results might reflect the differentiation or deviation of LCNEC toward an epithelial nature irrespective of neuroendocrine tumor lineage. In conclusion, the present comparative study of LCNEC and SCLC defined the similarities and differences between these cancers, and showed the biologically and clinicopathologically overlapping spectrum of the tumor lineage.

Significance of increased apoptosis and Bax expression in human small intestinal adenocarcinoma

Human small intestine accounts for 75% of the gastrointestinal (GI) length but for only 1-5% of GI tumors. The reason remains as yet unclearly understood. Our study was designed to examine whether increased apoptosis and expression of related genes/proteins, especially those of the Bcl-2 family, contribute to this difference. For this purpose, 77 samples from patients were examined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and immunohistochemistry, including 40 cases from normal small intestine (jejunum), 7 cases from jejunum and ileum adenocarcinomas, and 30 cases from normal colon. The results showed that a significantly higher level of enterocyte apoptosis was observed in normal small intestine compared with small intestinal adenocarcinomas and normal colon (median of apoptotic index, 15.2% vs 0.1% and 1.6%, p<0.01). A similar pattern was observed for Bax (expression-positive, 77.5% vs 28.6% and 53.3%, p<0.05) but not for Bcl-2 (42.5% vs 42.9% and 46.7%, p>0.05) or Bax/Bcl-2 ratio (percent of samples having a ratio > or =1, 45.0% vs 14.3% and 36.7%, p>0.05). In conclusion, increased apoptosis and expression of Bax, not Bcl-2 or the Bax/Bcl-2 ratio, may play some role in the relatively lower incidence of human small intestinal carcinomas. However, more studies are required for a better understanding of these changes.

Autopsy case of primary small cell carcinoma of the urinary bladder: KIT and PDGFRA expression and mutations

The author reports a rare autopsy case of primary small cell carcinoma of the urinary bladder with an emphasis on KIT and platelet-derived growth factor receptor-alpha (PDGFRA) genes. An 81-year-old man was admitted to Shizuoka City Shimizu Hospital because of dysuria. Cytology of the urine showed small carcinoma cells. Transurethral bladder tumorectomy indicated small cell carcinoma, and the patient was treated by radiation and chemotherapy. The patient died, however, of systemic metastasis 2 months after the first presentation. An autopsy showed a bladder small cell carcinoma and it systemic metastasis. Immunohistochemistry of the tumorectomy and autopsy specimens was positive for cytokeratins, neuron-specific enolase, synaptophysin, CD56, KIT and PDGFRA, and negative for chromogranin and thyroid transcriptional factor-1. Polymerase chain reaction-direct sequencing showed no mutations of KIT (exons 9, 11, 13 and 17) or PDGFRA (exons 12 and 18) genes in the tumorectomy specimens and was non-contributory due to DNA damage in autopsy specimens. The present case is the first case of primary small cell carcinoma of the urinary bladder involving examination of KIT and PDGFRA expression and KIT and PDGFRA gene mutations.

Primary small cell carcinoma of the mediastinum: a case report with immunohistochemical and molecular genetic analyses of KIT and PDGFRA genes

The author reports herein an extremely rare case of primary small cell carcinoma of the mediastinum with an emphasis on KIT and PDGFRA genes. A 66-year-old man was found to have a mediastinal tumor on a routine chest X-ray examination, and was admitted to our hospital. Imaging modalities revealed a 5 x 4 cm tumor in the middle mediastinum near the bronchial carina. No other tumors were detected in the body including the lungs. Video-assisted thoracoscopy confirmed the mediastinal tumor, and a large incisional biopsy was performed. The tumor was histologically small cell carcinoma. An immunohistochemical study revealed positive reactions for cytokeratins (AE1/3, polyclonal), synaptophysin, neuron-specific enolase, CD56, KIT, and PDGFRA, and negative reactions for chromogranin, CEA, CD45, CD20, and CD3. Ki-67 labeling showed a value of 80%. A molecular genetic analysis using PCR-direct sequencing identified no mutations of KIT (exons 9, 11, 13, and 17) and PDGFRA (exons 12 and 18) genes. The patient received radiation and chemotherapy, and the tumor was fully resolved. The patient has remained free of recurrence for 6 years after the first presentation. The present case is the first reported case of primary small cell carcinoma of the mediastinum with an examination of KIT and PDGFRA expressions and KIT and PDFGRA gene mutations.