Application of fluorescence in situ hybridization as a diagnostic tool in melanocytic lesions, using paraffin wax-embedded tissues and imprint-cytology specimens.

BACKGROUND: Accurate histopathological diagnosis of certain melanocytic skin lesions as benign or malignant can be notoriously difficult. Recently, four-colour fluorescence in situ hybridization (FISH) has emerged as an important tool for classifying these lesions. AIM: To evaluate the sensitivity and specificity of a melanoma FISH probe kit for accurate diagnosis of melanocytic tumours, and to validate its use with imprint-cytology specimens from the cut surface of tumours. METHODS: In total, 50 melanocytic skin lesions (31 malignant melanomas, 10 benign melanocytic naevi, and 9 histologically challenging benign melanocytic skin lesions) were evaluated. The samples comprise 47 tissue specimens embedded in paraffin wax, and three imprint-cytology specimens from the cut surface of melanomas. FISH was performed using four locus-specific identifier probes [Ras responsive element binding protein (RREB)1, myeloblastosis viral oncogene homologue (MYB), cyclin (CCN)D1 and centromere of chromosome (CEP)6], and results were compared with the clinical long-term follow-up and histopathological diagnosis data. RESULTS: The melanoma FISH probe distinguished between naevi and melanomas with a sensitivity of 100% and a specificity of 94.1%. The most sensitive criterion was a gain in 6p25 (RREB1), seen in 100% of cases, followed by CEP6-related MYB loss (48.1%), CCND1 gain (37%) and MYB gain (22.2%). More than three-quarters (77.8%) of melanomas were positive for two or more criteria. Positive FISH results were also obtained for the imprint-cytology specimens. CONCLUSIONS: FISH is a valuable diagnostic tool for differentiating between benign and malignant melanocytic lesions, providing a high degree of sensitivity and specificity. The probes displayed exceptional discriminative capacity in difficult or ambiguous lesions. To our knowledge, his is the first reported use of imprint-cytology specimens for FISH diagnosis.

[Late metastasis in thyroid gland after nephrectomy for renal clear cell carcinoma]. / Metástasis tardía en glándula tiroidea tras nefrectomia por carcinoma renal de células claras.

Renal carcinoma natural history is unpredictable. Spontaneous metastases regression after nephrectomy, as well as late recurrence are suggestive of this peculiar human neoplasm. tumor metastases localized to thyroid gland are uncommon in clinical practice; and carcinoma of the kidney, breast, lung, melanoma and gastrointestinal tract tumors are responsible for the majority of them. This paper reports on a patient with metachronous thyroid gland metastases after fourteen years of renal carcinoma nephrectomy, with one year after hemithyroidectomy recurrence on cervical striated muscle followed by surgical excision. Therapeutical aspects are briefly reviewed in literature, emphasizing surgical treatment and the need of all-life follow-up, with more alert attitude toward thyroid gland after renal cell carcinoma nephrectomy.