Modern comprehensive diagnostics and high-quality morphological diagnosis are important conditions for developing an optimal treatment algorithm for suspected recurrence of breast cancer. Our own clinical example shows the importance of a multimodal approach to the differential diagnosis of secondary tumor lesions. Thanks to modern clinical and radiological diagnostics, interventional technologies, high-quality morphological analysis and close interaction of all members of the multidisciplinary team, it was possible to verify a non-tumor lesion (sarcoidosis) in a patient with suspected relapse of breast cancer and plan the correct treatment tactics.