Keratin immunohistochemistry detects clinically significant metastases in bone marrow biopsy specimens in women with lobular breast carcinoma.

Some patients with breast cancer currently undergo bone marrow biopsy to make clinical decisions regarding therapy; however, lobular carcinoma can be difficult to detect in routine histologic sections. The authors reviewed retrospectively all available bone marrow biopsies from patients with lobular carcinoma diagnosed between January, 1, 1989, and September, 25, 1997, at the City of Hope National Medical Center to identify useful morphologic features and to determine the utility of pan-keratin immunohistochemical (IHC) staining. A total of 65 biopsies from 54 patients were reviewed. Thirteen of the 65 biopsies were classified initially as containing metastatic tumor based on histologic features alone. With the addition of keratin IHC, seven additional cases of metastatic disease were detected. Forty of the 54 patients received stem cell replacement or autologous bone marrow transplantation. Disease-free survival after high-dose chemotherapy with stem cell replacement or autologous bone marrow transplantation was stratified into three groups based on hematoxylin and eosin (H&E) staining and IHC results. Two-year disease-free survival was 33% for the H&E-/IHC+ group versus 90% for the H&E-/IHC- group (p = 0.005) among patients clinically free of disease at the time of stem cell replacement or autologous bone marrow transplantation. Two-year disease-free survival was 0% in the H&E+/IHC+ group (p = 0.04, compared with the H&E-/ IHC+ group). The authors conclude that routine morphologic examination without the aid of keratin IHC is unreliable in detecting clinically relevant metastatic lobular carcinoma in bone marrow biopsies. These findings suggest that pan-keratin immunostaining may be indicated on bone marrow biopsy specimens from lobular carcinoma patients if the biopsy appears histologically negative for metastatic tumor on H&E sections.

Immunoreactivity for epithelial and neuroendocrine antibodies are useful in the differential diagnosis of lung carcinomas.

The histologic classification of pulmonary neoplasms can have important implications regarding appropriate management of patients. Although the histologic classification of lung tumors is predominantly based on morphology, ancillary studies such as immunohistochemistry can be used in difficult cases, and the diagnosis of large cell neuroendocrine carcinoma requires confirmation of neuroendocrine differentiation by immunohistochemistry or electron microscopy. We immunostained 142 lung tumors for B72.3, keratin 34betaE12, keratin 7, keratin 14, keratin 17, synaptophysin, and chromogranin to determine the utility of neuroendocrine markers and epithelial markers in the differential diagnosis. Among neuroendocrine carcinomas (small cell carcinoma and large cell neuroendocrine carcinoma), 84% (37 of 44) were chromogranin positive, 64% (21 of 36 small cell, 6 of 6 large cell neuroendocrine) were synaptophysin positive, 5% (2 of 43) were keratin 34betaE12 positive, 9% (4 of 44) were keratin 7 positive, and 5% (2 of 37) of small cell carcinomas and 50% (3 of 6) of large cell neuroendocrine carcinomas were B72.3 positive. Among non-neuroendocrine carcinomas, 5% (5 of 98) were chromogranin positive, 3% (3 of 96) were synaptophysin positive, and 97% (95 of 98) were positive for either keratin 34betaE12 or keratin 7 and 99% (97 of 98) were positive for either keratin 34betaE12, keratin 7 or B72.3. An antibody panel consisting of keratin 7, keratin 34betaE12, chromogranin, and synaptophysin separated 132 of 141 tumors (94%) into distinct groups. We conclude that immunostaining with both neuroendocrine markers and epithelial markers can be useful in the differential diagnosis of lung neoplasms.

Microsatellite instability and K-ras mutations in patients with ulcerative colitis.

Patients with inflammatory bowel disease (IBD), particularly ulcerative colitis (UC), have an increased incidence of colorectal carcinoma. The underlying mechanism is unknown, but we postulated that microsatellite instability (MSI) might predispose the colonic mucosa of UC patients to mutations, thereby increasing their cancer risk. We also sought to determine the frequency of K-ras mutations, to determine whether MSI predisposed to K-ras mutations and to compare the molecular phenotype of biopsy and resection specimens in the same patient. We also sought to determine whether molecular alterations found in biopsy specimens presaged their presence in subsequent resection specimens. Two hundred fifty-eight specimens from 52 patients were examined for K-ras mutations by direct sequencing. Seventy-one of the specimens were neoplastic. MSI was evaluated after polymerase chain reaction (PCR) amplification using primers directed at 8 microsatellite loci. Of the patients, 18.2% had K-ras mutations, and 30.8% had MSI in at least 1 locus. Of K-ras mutations, 81.8% were G to A substitutions involving the second nucleotide of codons 12 or 13. Only 0.7% of the samples showed a high level of MSI. No relationship existed between MSI and K-ras mutations, even in the 2 samples with high-level MSI. The numbers are small, but it appeared that MSI in biopsies failed to predict its presence in resection specimens. In contrast, K-ras mutations present in biopsy specimens tended to predict their presence in resections. K-ras mutations were found predominantly in neoplastic mucosae, whereas MSI was found predominantly in regenerative mucosae. The lack of any relationship between MSI and K-ras mutations suggests that MSI in the UC replicative mucosa does not predispose to colonic neoplasia via a K-ras-mediated pathway. This is probably related to the fact that the MSI is generally low-level MSI.

Adenoma-carcinoid tumors of the colon.

OBJECTIVE: Neoplastic lesions containing both an adenomatous component and a carcinoid component are rare. To our knowledge, only two such lesions have been reported previously in the large intestine. We report two additional cases to further delineate the histologic features of these lesions and discuss their possible origin. DESIGN: Cases from the surgical pathology files, including consultation material, of the University of Cincinnati (Ohio) were reviewed. PATIENTS: One patient refused repeat colonoscopy at 6 months and subsequently was lost to follow-up. The other patient died 26 months after a hemicolectomy without evidence of recurrence. RESULTS: One lesion represents a collision tumor in which the two histologic components lay adjacent to one another without intermingling. The other is a composite tumor in which the components intermingled in such a way that in some areas the two components were difficult to distinguish from one another. CONCLUSIONS: Although both lesions contain dual components, we believe they are fundamentally different and that they arose from different mechanisms. Definite conclusions regarding prognosis cannot be made owing to the rarity of these lesions; however, there is no evidence to suggest they behave aggressively.

Cytokeratin 14 expression in epithelial neoplasms: a survey of 435 cases with emphasis on its value in differentiating squamous cell carcinomas from other epithelial tumours.

AIMS: The tissue distribution of cytokeratin 14 (CK14) in epithelial neoplasms is not well defined. We have evaluated 435 cases of epithelial neoplasm of various origins with cytokeratin 14 monoclonal antibody with special attention to possible use in differential diagnosis. METHODS AND RESULTS: Immunohistochemistry (ABC-HRP method) was performed for detection of CK14. We found that the expression of cytokeratin 14 was generally restricted to: (i) the majority of cases of squamous cell carcinoma regardless of origin (67/74) and degree of differentiation; (ii) neoplasms with focal squamous differentiation, including endometrial, and ovarian adenocarcinoma, malignant mesothelioma and transitional cell carcinoma; (iii) thymoma (8/8); (iv) myoepithelial components of salivary gland pleomorphic adenoma (3/4); and (v) oncocytic neoplasms, including thyroid Hurthle cell adenoma (1/1) and salivary gland Warthin's tumour (2/2). CONCLUSION: CK14 protein is a useful marker in differential diagnosis of squamous cell carcinomas.

Multifocal neoplasia involving the colon and appendix in ulcerative colitis: pathological and molecular features.

A patient with ulcerative colitis, extensive dysplasia, multifocal colon cancer, and an appendiceal cystadenoma is described. A 48-year-old man with a 26-year history of ulcerative colitis (UC) had extensive dysplasia involving nearly the entire colon and four dysplasia-associated mass lesions (DALMs). Four invasive adenocarcinomas were present. This case is the first documentation of a DALM (mucinous cystadenoma) arising in the appendix in the setting of UC. The genetic alterations present in the various lesions were analyzed. The molecular profiles of the neoplastic lesions differed. Mutations were found in p53 and ras genes, and one site showed microsatellite instability in a single genetic locus. These molecular abnormalities develop before invasive cancer develops, and may undergo clonal expansion to create large mucosal patches containing certain cells with genetic alterations. The diversity of the early changes suggests that the recurrent inflammation characteristic of long-standing UC randomly damages genes known to participate in colon carcinogenesis and that it affects multiple target genes. The findings also support a multiclonal origin of synchronous tumors because the molecular phenotypes of the preinvasive lesions differed at various sites.