Immunohistochemical staining was performed on 145 biopsies with a diagnosis of undifferentiated or poorly differentiated tumor in order to classify them into lymphoid, epithelial, or mesenchymal in origin. It was possible to arrive at a histogenetic diagnosis on immunostaining in 85.5% of cases. Immunostaining confirmed the diagnosis in 32.4% and contributed to diagnosis in 53.1%. Malignant lymphoma was the most common diagnosis (35.9%), followed by carcinoma (23.4%). A panel of antibodies consisting of anti-common leucocyte antigen (LCA), anti-epithelial membrane antigen (EMA), anti-cytokeratin (CK), anti-low to intermediate molecular weight cytokeratin (CAM 5.2), anti-S-100 protein (S-100), and anti-vimentin (VM) may resolve, to a large extent, some of the common diagnostic problems.

Routine method of decalcification involves fixation of bony fragments overnight in 10% buffered formalin, followed by decalcification in an acid decalcifying agent comprising 5% nitric acid for soft bones and 10% nitric acid for hard bones. After rinsing under running water, the fragments are processed in a tissue processor using a routine standard protocol that would normally take over 3 days turnaround time. A total of 15 300 unfixed bone specimens, received in our laboratory between 2005 and 2009, were processed by a modified method incorporating simultaneous fixation and decalcification. Specifically, soft bones were placed in 5% formol nitric acid and hard bones were placed in 10% formol nitric acid to achieve fixation and decalcification. Very sclerotic hard bone or large bone fragments were placed in 10% nitric acid and additionally subjected to heat at 37uC in an incubator for 5-6 hours. After achieving satisfactory decalcification, the fragments were subsequently processed using a tissue processor. Sections of 4-5 mm thickness were obtained and stained with hematoxylin and eosin. Our laboratory handles up to 200 specimens per day requiring decalcification processes. Prior to implementing simultaneous fixation and decalcification processes, decalcification was achieved in 5-6 days; after implementing the process modification, the turn around time was decreased by 2-3 days, demonstrating increased efficiency without added cost.

Extraskeletal myxoid chondrosarcoma is a rare soft-tissue sarcoma of the extremities that is considered to be indolent, but yet it has a capacity for multiple recurrences and lung metastasis. In a 23-year period, 10 cases of this rare tumor were reported in this institute. The authors studied the clinicopathologic features, including histochemical and immunohistochemical reactions, of these 10 cases, with a view to evaluate whether any constant pattern emerged. The histologic features include a lobular or nodular growth pattern, periodic acid-Schiff's stain positivity, diastase sensitivity, alcian blue positivity with and without pretreatment by testicular hyaluronidase, lack of epithelial markers, and positivity for S-100 protein and vimentin. The purpose of this article is to stress that the above-mentioned features are of immense help in delineating this rare tumor from other tumors associated with myxoid and chondroid differentiation. The authors did not find any consistent relationship between site, cellularity, and development of lung metastasis. Int J Surg Pathol 5(3/4): [77][78][79][80][81][82] 1997