The utility of immunohistochemistry for providing genetic information on tumors.

With advances in immunohistochemical technology and growing knowledge of the molecular genetics of tumors, immunohistochemistry is playing an increasingly important role in providing genetic information for tumors. Specific chromosomal translocations can be demonstrated through detection of the protein product of one of the genes involved in gene fusion (such as BCL2, cyclin D, and ALK). Some mutations can be detected by (1) aberrant localization of the protein product (such as β-catenin and nucleophosmin), (2) abnormal accumulation of the protein product as a result of stabilization of the protein (such as p53), and (3) mutation-specific antibodies directed against the mutant protein (such as isocitrate dehydrogenase gene R132H mutation, epidermal growth factor receptor gene L858R and exon 19 deletion mutations, and BRAF gene V600E mutation).

Spontaneous complete regression of gastric large-cell neuroendocrine carcinoma: mediated by cytomegalovirus-induced cross-autoimmunity?

Spontaneous regression of malignant tumour is a rare phenomenon. This report describes such an occurrence in a gastric large cell neuroendocrine carcinoma of a 77-year-old man. The patient presented with dyspepsia, and biopsy of the fungating mass in the cardia showed a high grade neuroendocrine carcinoma.

Nuclear inclusions and pseudoinclusions: friends or foes of the surgical pathologist?

Abnormal substances in the nuclei that can be observed by light microscopy are often broadly referred to as nuclear inclusions. Although their recognition in the appropriate clinicopathological settings can aid in the diagnosis of some disease entities and tumor types, they can also be a source of error. There are 2 morphologically distinct types of inclusions with different mechanisms of formation and diagnostic significance, including bona fide nuclear inclusions and nuclear pseudoinclusions.

Sporadic hemangioblastoma of the kidney: an underrecognized pseudomalignant tumor?

Hemangioblastoma is a benign tumor that can occur sporadically, or in association with von Hippel-Lindau disease in approximately one-quarter of the cases. Only exceptionally does it occur outside the central nervous system. This report describes 2 cases of sporadic renal hemangioblastoma, with 1 patient presenting with hematuria and polycythemia, and the other low back pain.