Time needed for rinsing the decalcification specimen by tap water.

Objectives: To determine a proper time for neutralizing the decalcified specimen by rinsing with tap water. Methods: Fix pork from fresh market in routine fixative for 24 hours, put into 5% nitric acid for 24 hours to 7 days. Then rinse in running tap water for 1-48 hours. Process and cut the specimens into slide, attain with H&E stain. Distribute to three pathologists to evaluate the quality of staining and microscopic detail. Results: Neutralizing for 2 hours or longer yields similar microscopic to the specimen that soaked in acid for 72 hours or less. The histologic feature is not recovered in the soaked in acid longer than 72 hours, no matter how long it is neutralized. Discussion: The result shows no benefit in rinsing the decalcified specimen longer than 2 hours, and soaking in acid longer than 72 hours causes permanent artifact.

Giant cell tumor of the bone : Radiographic evaluation.

Giant cell tumor is a relatively common skeletal tumor with radiographically characteristic appearance in a predictable location. Clinical data from 66 patients with radiographical and from 37 patients with pathological diagnosis of giant cell tumor of the bone in Siriraj Hospital were retrospectively reviewed from June 1995 - December 2001. Histological grading was classified as grade I 78%, grade II 19%, and grade III 3%. Female patients accounted for a alight majority (F : M = 1.54 : 1). Eighty percent of the tumors were in the expected locations at the end of long bone (femur, tibia, radius, and humerus), where as a few lesions were located at atypical sites such as sacrum, talus, ulna, rib, or scapula. One patient had pulmonary metastasis and one patient had multifocal lesions. The aggressiveness of radiographic findings was evaluated and based on the following criterias : breaking of cortex, soft tissue involvement, joint involvement and large tumor size in correlation with histological grading and tumor recurrence. Our study showed no correlation between tumor size and histological grading.

Clinical and histopathological classification of nasal polyps in Thais.

One hundred and forty five patients with nasal polyps (NP) who underwent a first operation at the Department of Otolaryngology, Faculty of Medicine Siriraj Hospital during the 2-year period January 1998 to December 1999, were studied to determine the incidence of clinical and histolopathologic types of NP in Thai patients. The clinical types of NP were classified into 5 groups, using Stammberger's criteria i.e. isolated polyps (IP); antrochoanal polyps (ACP); NP and chronic rhinosinusitis (NPCRS) associated with non-eosinophilic infiltration; NPCRS associated with eosinophilic infiltration or NP with asthma (NPA); and NP with specific diseases (NPSD). The histopathologic types were classified into 4 types, using Hellquist's criteria i.e. Type I, edematous, eosinophilic (allergic) polyps; Type II, chronic inflammatory (fibroinflammatory) polyps; Type III, polyps with hyperplasia of seromucinous glands; and Type IV, polyps with stromal atypia. There were 86 males (59.3%) and 59 females (40.7%), with a male : female ratio = 1.5 : 1. The mean age was 36.1 + 16.5 years, ranging from 9 to 74 years. The mean duration of symptoms was 63.6 + 75.2 months, ranging from 1-420 months. The clinical classification study showed that 17 patients (11.7%) had IP, 13 patients (8.9%) had ACP, 105 patients (72.4%) had NPCRS, 5 patients (3.5%) had NPA, and 5 patients (3.5%) had NPSD (one case of Katargener's syndrome, bronchiectasis, aspirin intolerance, immotile cilia syndrome, and AIDS respectively). The histopathologic study showed that 17 specimens (11.7%) were Type I, 118 specimens (81.4%) were Type II, 9 specimens (6.2%) were Type III, and 1 specimen (0.7%) was Type IV. In the group of patients with NPCRS (105 patients), the most common histopathologic type was type II (86 patients, 81.9%). Type I and Type III were found in 12 patients (11.4%) and 7 patients (6.7%) respectively. The incidence of eosinophilic polyps in the groups of NPCRS was only 18.1% (Type I + Type III). This finding is different from that of NP in the western countries, in which the incidence of eosinophilic polyps is 80-90%. The pathogenetic mechanism underlying this difference is still not known. Is this difference due to racial or genetic factors, or geographic differences? The answers to these question are to be studied further.