Introduction: Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a rare subtype of CD30-positive and ALK- negative (anaplastic lymphoma kinase) T cell lymphoma, which can develop in the pericapsular fibrous tissue and the late seromas around breast implants. If BIA-ALCL is suspected, an adequate diagnostic flow is essential. Materials and methods: A flowchart of the procedures performed in the diagnostic investigation is discussed, associating a clinical case, and conducting a review on the topic. Results: In the assessment of late and recurrent periprosthetic seromas, prior communication from the surgeon and the pathologist is essential, aiming at the adequate collection and storage of the aspirated material. The material must be promptly fractionated for microbiological assessment by culture, immediate or transoperative cytologic assessment, immunophenotyping by flow cytometry (10 mL), direct cytopathological examination, and obtaining cell block material (50 mL). For flow cytometry, the material must be sent fresh, 70% alcohol or 10% buffered formalin can be added for the other procedures. If it is impossible to send the aspirated fluid to the laboratory in less than six hours, it can be temporarily stored in a refrigerator at 4°C. Immunophenotyping should be extensive, always assessing the expression of CD30 and ALK, regardless of cytological aspects. In cases of late and recurrent seromas in which BIA-ALCL is considered, even if initially discarded, it is suggested to perform capsulectomy with the removal of the prosthesis or careful clinical and laboratory monitoring. Conclusion: The diagnostic flowchart is essential, aiming at false-negative tests.

Introduction: Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a rare entity. As a result, care in the diagnostic flowchart is not systematized and known by all mastologists. Non-systematic evaluation can lead to false-negative assessments, making it crucial to have systematic knowledge about the subject. Methods: The Research Ethics Committee of the Hospital de Câncer de Barretos approved this study, under the number 23026719.5.0000.5437/2019. We sought to conduct an integrative review on the subject, aiming at identifying the diagnostic flowchart and therapeutic care to be adopted by mastologists. Results: BIA-ALCL diagnosis should be considered in patients with peri-implant seroma when the implant was placed for more than a year. Despite being more associated with textured implants, the disease was also identified in smooth implants. In clinical practice, breast ultrasound is the examination of choice. The main finding is peri-implant seroma, with puncture. Breast magnetic resonance imaging can help evaluate implant integrity. Positron emission tomography-computed tomography (PET-CT) can be used in high suspicion or confirmed cases, improving the staging. Some precautions are essential in the care of the collected fluid; otherwise, it can lead to false negatives. Cytology should be performed on the day of collection, in less than 6 hours. Centrifuging the fluid collected should be considered in order to obtain a smaller volume but with high cellularity. The centrifuged material can be processed to form a paraffin block (cell block), in which the Wright-Giemsa stain will be used. The material can be sent immediately or after adding 50% alcohol. Surgery should be indicated in cases of tumor mass, high clinical suspicion, or recurrent seroma. In these cases, drainage of the peri-implant content and capsulectomy with concomitant removal of the breast implant should be carried out. Bilateral implant removal is recommended if BIA-ALCL is confirmed; however, in case of suspected diagnosis, the indication becomes questionable, and the surgeon must discuss the situation with the patient. Conclusion: Diagnostic systematization reduces the possibility of false-negative results, improving the care described above.