Multiple cutaneous lymphoproliferative disorders showing a retained tumor clone by T ‐cell receptor gene rearrangement analysis: a case series of four patients and review of the literature

Background Mycosis fungoides ( MF ) is the most common primary cutaneous T ‐cell lymphoma ( CTCL ), followed by CD 30+ lymphoproliferative disorders, including lymphomatoid papulosis ( L y P ) and primary cutaneous anaplastic large cell lymphoma (pc ALCL ). The objective was to report on a series of patients with different types of CTCL at different times in their clinical course, with a focus on clonality studies. Methods Four patients with multiple diagnoses of CTCL s were identified. The clinical information, treatment interventions, and histopathology were reviewed. T ‐cell receptor ( TCR ) gene rearrangement studies were performed on all available specimens. Results The four patients carried diagnoses of: (1) pc ALCL and MF ; (2) pc ALCL , L y P , and pc ALCL ; (3) L y P , MF , and pc ALCL ; (4) L y P , pc ALCL , and MF ; each with characteristic presentation and histopathologic findings. The results of the TCR polymerase chain reaction showed that all tumors expressed and retained a TCR clone(s) as follows: (1) biallelic clone; (2) single clone; (3) biallelic clone with additional clone; and (4) single clone, respectively. Conclusion We report a series of four cases of individual patients with coexisting diagnoses of some combination of MF , L y P , and pc ALCL , whose lesions presented in nontraditional sequence and demonstrated a retained clone by gene rearrangement analysis.