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Dear Editor, Classic Hodgkin lymphoma (CHL) is a B-cell-derived monoclonal lymphoid neoplasm. The key features in morphological diagnosis are mononuclear Hodgkin cells and multinucleated Reed–Sternberg cells. A background of mixed inflammatory cellularity including neutrophils, eosinophils, plasma cells, and lymphocytes is helpful. In cases suspecting of lymphoma, a proper screening and approach are required to not only expedite the diagnostic steps but also save the tissue for required workup steps. Touch preparation (TP) is considered a rapid and simple technique with nearly general availability in any frozen section unit. In this article, we are going to emphasize the importance of TP in early CHL screening. CHL is morphologically diagnosed by the presence of mononuclear Hodgkin cells and multinucleated Reed–Sternberg cells confirmed with the appropriate immunohistochemistry profile in the right clinical context. A clinical suspicion of lymphoma and then considering CHL as one of the potential causes of that lymphoma is the sequence of steps in a proper diagnosis. Reed–Sternberg cells have a unique morphology that makes them single out from the background. They usually have at least two nuclear lobes with abundant cytoplasm. They are usually larger than background lymphocytes and inflammatory cells. During an operation for an unknown malignancy, since the patient's clinical status and potential comorbidities may increase some urgency to both clinician and pathologist to make a paramount diagnosis, the role of TP becomes more crucial. Although the hematoxylin and eosin and permanent slide preparation with appropriate immunohistochemistry profile would remain the diagnostic modality of choice, the role of TP could be potentially emphasized as the screening modality of choice that has some superiority to frozen section samples in these situations. Preparation of TP slides has less budgetary effect and faster assessment compared to the conventional frozen section samples. This might be of significant importance in high-turnover frozen section units. We present a 40-year-old female with recent history of pruritis, cough, night sweats, and losing weight in the past few months. The primary care physician requested imaging studies and mediastinal mass was detected. The patient did not have any outstanding past medical history. A surgical biopsy was performed and intraoperative consultation was requested. Multiple fragments of tissue aggregating 1.2 cm × 1 cm × 0.9 cm were received in the frozen section unit and a TP smear was prepared Figure 1. Few suggestive of Reed–Sternberg cells identified in a background of mixed inflammatory cells and the possibility of lymphoma with favor of Hodgkin lymphoma was offered during the intraoperative consultation. The diagnosis of CHL was later confirmed on histology with the appropriate immunohistochemistry panel. As noted from the TP, a high suspicion for a lymphoproliferative neoplasm, a proper TP preparation, and a thorough examination of the specimen could be very much helpful to identify the Reed–Sternberg cells. Since flow cytometry has limited protentional value in making a diagnosis of CHL in routine practice,1 with the help of TP, we can not only narrow the differential diagnosis and save the tissue for histology examination but also delay or avoid cost-effective flow cytometry at this step.Figure 1: Touch preparation smear of the mediastinal mass/lesion at ×40. It shows a large cell with two nuclear lobes (arrow) with a background of mixed inflammatory cellsCHL has four subtypes. For example, in the nodular sclerosis variant, mediastinal involvement occurs in approximately 80% of cases.2 Even though in literature, the diagnostic accuracy of Hodgkin lymphoma is estimated to be around 66% by TP,3 still has a significant value to apply for screening in suspected cases. Although CHL could be difficult to identify on TP due to its polymorphous background, a careful examination in highly suspicious clinical cases could help to find Reed–Sternberg cells and prioritize the tissue for histology and immunohistochemistry.4 A pitfall in TP of CHL is that sometimes the Reed–Sternberg cells may cluster together which may mimic a metastatic carcinoma to the lymph node.5 In this case, a high clinical suspicion of CHL and lack of previous primary malignancy may help to narrow the differential diagnosis. Understanding the limitation of TP cytology including limited submitted tissue that may not be representative or expert level in the preparation of the TP should also be considered. In summary, the preferred method for diagnosis of lymphoma, including CHL is excision of the lymph node to evaluate the architecture and cytologic features. On the other hand, during intraoperative consultation, TP can be the modality of choice to screen and identify CHL from non-Hodgkin lymphoma or other neoplasms.6 It is considered an easy and rapid test with reasonable reproducibility in highly suspected clinical cases.
Payam S. Pahlavan (Mon,) studied this question.