Lymph node harvest in colorectal adenocarcinoma specimens: the impact of improved fixation and examination procedures.

A review of 1050 pathology reports from colorectal adenocarcinoma specimens examined at the Department of Pathology, Sørlandet sykehus HF, Kristiansand, Norway during the period 1995-2006 revealed a poor performance of most doctors concerning lymph node harvest. A mean of 8.1 nodes per specimen (range 12.3-2.1) and a mean proportion of 22.3% of specimens with ≥12 lymph nodes (range 47.1-0%) were found. A small pilot study was undertaken in 2007 to evaluate the effect of prolonged formalin fixation and the use of a special lymph node fixative [glacial acetic acid, ethanol, water and formaldehyde (GEWF) solution] with regard to the number of retrieved nodes. This showed that one extra day formalin fixation and the use of GEWF solution considerably enhanced the detection of lymph nodes, particularly those of smaller size. Based on these findings, our routines concerning handling of colorectal cancer specimens were changed during 2007. After this time all specimens have been fixed in a mixture of GEWF solution and formalin for at least 48 h and the doctors have been encouraged to find as many lymph nodes as possible. In cases revealing <12 nodes after microscopical examination, the specimens have been re-examined and searched for additional nodes. A review of lymph node retrieval in 423 cases of colorectal cancer during the period 2008-2010 showed that the mean number of nodes per specimen had increased to 16.8 (range 29.0-13.3) and the proportion of specimens with ≥12 nodes to 78.0% (range 96.8-63.6%). Thus, these changes of routines which were easy to implement without significant extra costs have considerably improved lymph node harvest at our department. The use of a special lymph node fixative (e.g. GEWF solution) is highly recommended not only for detection of nodes in colorectal specimens, but also for retrieval of lymph nodes embedded in fat tissue generally.

Lymph node harvest in colon cancer specimens depends on tumour factors, patients and doctors, but foremost on specimen handling.

There are good indications that the number of lymph nodes found in the specimen after resections for colon cancer somehow has a bearing on prognosis. Many factors have been reported in the literature to influence lymph node retrieval. We wanted to assess these closer with special focus on the pathology handling process in our own practice. A range of international literature was reviewed to study what has been found to influence lymph node harvest. A questionnaire was sent to 13 renowned national and international institutions to explore their handling of the colon cancer specimens to obtain a histological diagnosis. A retrospective, hospital audit was undertaken to examine if the number of lymph nodes and staging after examinations of the specimens varied between individual pathologists. In the literature, tumour and patient characteristics, as well as the surgeon and the pathologist, are found to be influential, but it is difficult to ascertain which ones are truly essential. Fat solvents were found by several to increase the lymph node yield, although some also opposed this finding. Our questionnaire showed some variations in the routines of each Department. A junior pathologist was more likely to inspect the specimen first hand and not more than half employed specific lymph node detection strategies while three of 13 did not seek a minimum number of lymph nodes. Still every department had implemented a standard procedure for such examinations. The internal audit showed without doubt that the devotion of the pathologist secured significantly more lymph nodes from the specimen and this may also have detected more stage III cancers. Several tumour and individual patient characteristics, surgical approach and specimen handling may influence lymph node yield and theoretically, TNM staging. Our investigation specifically suggests that tissue handling by pathologists may be a prominent factor in lymph node harvest from colon cancer specimens.

Epidermal basaloid cell hyperplasia overlying dermatofibromas.

In a series of 1117 dermatofibromas (69% women and 31% men), there were 25 cases (2.2%) with basaloid cell hyperplasia (BCH) of the overlying epidermis. This type of hyperplasia, which closely resembled a basal cell carcinoma (BCC), was predominantly seen in men (14 vs. 11 cases). To determine the nature of these BCHs, we applied a panel of 18 antibodies that are commonly used to classify epithelial proliferations on 6 cases with sufficient amounts of BCH and on 20 BCCs of various types. The number of CK20-positive Merkel cells was found to be increased in 4 cases of BCH, whereas these cells were completely absent or reduced in all BCCs. The significance of this finding must be interpreted with caution, but it must be regarded as a promising method to distinguish between reactive BCHs and neoplastic BCCs. Except for this rather subtle finding, none of the antibodies used could discriminate between the 2 conditions.

Laser capture microdissection of bacterial cells targeted by fluorescence in situ hybridization.

Direct cultivation-independent sequence retrieval of unidentified bacteria from histological tissue sections has been limited by the difficulty of selectively isolating specific bacteria from a complex environment. Here, a new DNA isolation approach is presented for prokaryotic cells. By this method, a potentially pathogenic strain of the genus Brachyspira from formalin-fixed human colonic biopsies were visualized by fluorescence in situ hybridization (FISH) with a 16S rRNA-targeting oligonucleotide probe, followed by laser capture microdissection (LCM) of the targeted cells. Direct 16S rRNA gene PCR was performed from the dissected microcolonies, and the subsequent DNA sequence analysis identified the dissected bacterial cells as belonging to the Brachyspira aalborgi cluster 1. The advantage of this technique is the ability to combine the histological recognition of the specific bacteria within the tissue with molecular analysis of 16S rRNA gene or other genes of interest. This method is widely applicable for the identification of noncultivable bacteria and their gene pool from formalin-fixed paraffin-embedded tissue samples.

Amyloid myopathy presenting with distal atrophic weakness.

Amyloid myopathy is a rare complication of primary amyloidosis usually presenting with proximal muscle weakness. We report a woman with multiple myeloma in whom marked atrophy and weakness of finger flexor muscles were the first manifestations of systemic amyloidosis. Muscle biopsy revealed amyloid angiopathy with deposits of lambda light chains in vessel walls. The recognition of amyloid myopathy is important because clinical symptoms may respond to chemotherapy.