ABSTRACT
Peripheral primitive neuroectodermal tumor (pPNET) has some histologic resemblance to a classic central primitive neuroectodermal tumor (cPNET), however it is distinctively different from cPNET by its CD99 immunoreactivity, characteristic chromosomal translocation, t(11;22)(q24:q12) and EWS/FLI-1 chimeric mRNA. Peripheral PNETs have a predilection for soft tissues rather than for viscera. Only 15 cases of primary ovarian PNET have been reported, and only one case was proven to be pPNET. Ovarian PNET is an aggressive tumor. We report a case of a 40-year-old Thai woman with a Stage IIIb right ovarian PNET is an aggressive tumor. Despite debulking operation and vigorous adjuvant chemotherapy, the patient died of disease 6 months later. Grossly, the tumor was solid and cystic. Microscopically, the former displayed unique features mimicking cPNET, but the pPNET phenotype was validated by CD99 staining. The solid portion also contained mucin-producing gland-like structures, previously described as ependymal diffentiation. In the cystic portion, the histology demonstrated epithelial linning tissue resembling cystadenoma of borderline malignancy of the ovary. It is generally accepted that both cPNET and pPNETs can have polyphenotypic differentiation. PNETs can be originated from either totipotential germ cells, neural crest remnant or mullerian-derived cells.
ABSTRACT
Objective: To evaluate the validity of pathological diagnosis of cervical cone specimens prepared by frozen section compared with paraffin section. Study design: Diagnostic test evaluation. Setting: Pathology division, Department of Obstetrics and Gynecology, faculty of Medicine Siriraj Hospital, Mahidol University. Methods: Cervical cone specimens from 78 patients who underwent cold knife conization at Siriraj Hospital from October 1997 to September 1998 were processed by frozen section technique and the pathological diagnoses were made immediately. The remaining cone tissue from each specimen was processed to produce permanent paraffin sections for a final diagnosis. The frozen and permanent pathological diagnoses were compared. Results: The pathological diagnosis from frozen section was in complete agreement with the permanent section in 60.26% of patients. When the subjects were divided into three groups; normal and CIN I, CIN II-III and MIC and invasive cancer, the Kappa analysis for agreement of the pathological diagnoses between the two methods was 0.46 (fair agreement). For the diagnosis of invasive cancer by frozen section, the sensitivity, specificity, positive and negative predictive value, false negative and false positive were 62.5, 97, 71.4, 95.8, 37.5 and 1.9%, respectively. There were three cases of invasive cancer on permanent paraffin section which were diagnosed by frozen section as MIC in tow cases and CIN III in the other. Conclusion: Frozen section evaluation of a cervical cone specimen carries only a moderate degree of agreement with permanent paraffin section. For the diagnosis of invasive cancer in this study, frozen section has a low sensitivity and a high false negative rate. The diagnosis of microinvasive cancer was subject to significant error. The diagnosis of microinvasive cancer by frozen section needs additional careful review of the permanent section.
ABSTRACT
Over a 5-year period, 402 women with benign cystic teratoma of the ovaries were seen at Siriraj Hospital. Fifty patients had bilateral ovarian tumors (12.44%). In 47 of these patients, bilateral involvement was evident on clinical examination. One hundred and seventy three patients with a visually normal opposite ovary had 3 (1.16%) identifiable tumors in that ovary by incidental ovarian operations. This 1.16% incidence of occult covert bilaterally is quite low and suggests that routine bivalving of wedge resection of a clinically normal opposite ovary is not necessary since peri-tubo-ovarian adhesion, pain and adhesion, pain and infertility are the common result. However, the possibility of such an occult tumor is not zero.