RESUMO
Spindle epithelial tumor with thymus-like differentiation (SETTLE), a rare tumor of the thyroid gland, is difficult to diagnose irrespective of its unique morphology. It is usually misdiagnosed as synovial sarcoma, thymoma, teratoma, or other thyroid carcinomas. In the current case report, we detail a case of a 36-year-old male patient who presented with thyroid swelling that was initially misdiagnosed as papillary thyroid carcinoma instead of SETTLE. Based on fine needle aspiration, the tumor showed a variable pattern with features suggestive of follicular neoplasm in the right lobe and atypia of undetermined significance in the left lobe. Pathological examination showed multiple nodules on both the right and left lobes, with the largest nodule measuring 4.8 x 4.5 x 3 cm. On microscopic examination, a predominant papillary pattern was observed along with spindle cell areas. Immunohistochemistry revealed positive staining for thyroglobulin, CK, HMWCK, CD99, and BCL-2, which led to the diagnosis of SETTLE. The rare nature of the condition and the reduced awareness about it make this tumor a diagnostic challenge. This case report concludes that in case of any biphasic tumor with epithelial and spindle cells in the thyroid gland, it is important to consider the differential diagnosis of SETTLE. Immunohistochemistry is more useful for diagnosing SETTLE, and thus pathologists are encouraged to judiciously advise the patients for immunohistochemistry to establish accurate and efficient diagnosis.
RESUMO
Risk management constitutes an essential component of the Quality Management System (QMS) of medical laboratories. The international medical laboratory standard for quality and competence, International Standards Organization (ISO) 15189, in its 2012 version, specified risk management for the first time. Since then, there has been much focus on this subject. We authors aimed to develop a practical tool for risk management in a clinical laboratory that contains five major cyclical steps: risk identification, quantification, prioritization, mitigation, and surveillance. The method for risk identification was based on a questionnaire that was formulated by evaluating five major components of laboratory processes, namely i) Specimen, ii) Test system, iii) Reagent, iv) Environment, and v) Testing. All risks that would be identified using the questionnaire can be quantified by calculating the risk priority number (RPN) using the tool, failure modes, and effects analysis (FMEA). Based on the calculated RPN, identified risks then shall be prioritized and mitigated. Based on our collective laboratory management experience, we authors also enlisted and scheduled a few process-specific quality assurances (QA) activities. The listed QA activities intend to monitor new risk emergence and re-emergence of those previously mitigated ones. We authors believe that templates of risk identification, risk quantification, and risk surveillance presented in this article will serve as ready references for supervisors of clinical laboratories.
RESUMO
BACKGROUND: In case of difficulty in the interpretation of fine needle aspiration (FNA) smears of a thyroid nodule, histopathologic examination is advised to arrive at a definitive diagnosis. On rare occasions, a specific diagnosis may be given based on cytologic examination, but FNA is followed by infarction of the thyroid nodule, with resultant difficulty in interpretation or even misinterpretation of bistopathologic material. We report 2 such cases. CASES: Two cases were diagnosed as papillary thyroid carcinoma (PTC) by FNA cytology, but histopathology reports indicated colloid goiters with infarcted nodules. Review of histopathologic material showed features of PTC in the viable tissue at the periphery of nodules. Immunohistochemical study for galectin-3 and CD44 in 1 of the cases supported the diagnosis of PTC. CONCLUSION: We suggest that while reporting on an infarcted nodule in paraffin sections of a thyroidectomy specimen, the histopathologist should be careful to look thoroughly at its periphery for the surviving cells and their detailed morphologic features, especially if there is a prior FNA cytology report of a neoplasm.
