When supervising patients, a practicing physician daily faces various clinical and laboratory syndromes. To make a differential diagnosis for many conditions and diseases, the physician must have not only practical experience, but also a broad outlook, including in a number of related specialties. The pathomorphism of diseases, the atypical clinical presentation at the onset of the disease increasingly require the involvement of a multidisciplinary team to solve diagnostic puzzles. The presented clinical case considers the stages of inpatient diagnostic search in a patient with generalized lymphadenopathy. Exclusion of lymphoproliferative diseases became possible only after lymph node excision biopsy, by making an immunohistochemical study, bone marrow puncture, and trepanobiopsy. The nephrotic syndrome and the thyrotoxicosis syndrome have become the following stage of a differential diagnosis.