Clinical implications of cytogenetic studies in cutaneous t‐cell lymphoma (CTCL)

Detailed cytogenetic studies were performed in 41 patients with cutaneous T‐cell lymphoma (CTCL): four patients had limited plaques, 13 patients had generalized plaques, eight patients had cutaneous tumors, 16 patients had generalized erythroderma, and four additional patients, who had relatively benign chronic dermatosis, served as controls. Correlating the histologic and cytogenetic results in the various tissues, it was observed that 62% of the peripheral blood specimens were cytogenetically positive but only 49% were morphologically positive; in the lymph node the ratio was 80 versus 45%, and in the bone marrow, 6 versus 3%. These studies demonstrate that chromosome abnormalities are frequently detectable before morphologic changes become apparent. Chromosome banding preparations showed extensive and wide‐ranging heteroploidy; the #1 chromosome was most frequently involved in structural abnormalities while chromosomes #11, 21, and 22 were most frequently involved in numerical abnormalities. These cytogenetic findings support the impression that CTCL is a disease whose various clinical manifestations represent a chronologic sequence, with the cytogenetic findings paralleling the clinical symptoms: patients with minimal chromosomal changes had the best survival and the more extensive the chromosome abnormalities, the more advanced the clinical disease. Clone formation was seen in eight patients and this phenomenon, along with hyperdiploidy and near‐tetraploidy, was associated with a poor prognosis and short survival. We conclude that CTCL progresses from an early phase with extensive chromosomal abnormalities and lack of clone formation to a terminal phase with clone selection. Cytogenetic studies can, therefore, be of significant diagnostic and prognostic value in CTCL.