Histopathological difficulties in an adolescent lymphoma patient.

The B-cell lymphoma, unclassifiable, showing intermediate features typical for both diffuse large B-cell lymphoma (DLBCL) and classical Hodgkin lymphoma (HL) is a novel category of diffuse large B-cell lymphomas (DLBCL/HL), which has been described by the WHO classification in 2008. This rare type of lymphomas, previously called as gray zone lymphoma presents peculiar clinical, morphological and immunophenotypical patterns. In December 2011 a 17-year old male was diagnosed with mixed cellularity subtype of classical HL. His clinical stage was IV/BXS (abdominal bulky) with unfavourable prognosis. Because of the unusually extended disease (nodal-extranodal-bulky) a histological revision was performed. After an incomplete course of ABVD chemotherapy the patient's symptoms disappeared and regression was detected in the size of peripheral lymph nodes. The diagnosis changed into DLBCL/HL, so the treatment was modified to R-CHOP-14 regimen. After the administration of 3 cycles of R-CHOP-14, he achieved a complete metabolic remission (CMR), which was confirmed by a (18)FDG-PET/CT scan. Receiving further 4 cycles of R-CHOP-14 therapy the patient was still in CMR, but a PET negative large mass (70 × 30 mm) still remained visible in the abdominal region. Considering this residuum and the aggressive subtype of lymphoma he was referred for an autologous hemopoietic stem cell transplantation (AHSCT). After 2 cycles of R-DHAP regimen, successful CD34 positive stem cell collection was performed in August 2012. In September 2012, he underwent a R-BEAM conditioning followed by AHSCT. The next (18)FDG-PET/CT still detected CMR 100 days after the AHSCT. The patient was in excellent clinical condition and also in complete remission 15 months after the AHSCT. Upon this case, it should be underlined that the diagnosis may need revision if a patient represents atypical clinical signs and behavior, and the importance of cooperation between clinicians and pathologists is also strongly emphasized.