RESUMO
Background: Low-grade appendiceal mucinous neoplasms (LAMN) of the appendix have bland cytological features and well-differentiated morphology. Despite this, they may cause a pseudomyxoma peritonei (PMP) disease characterized by mucinous deposits in the peritoneal cavity and may exhibit malignant behavior. Aims and Objectives: In this study, we evaluated the clinical course and histopathological findings of LAMN. The rate of progression to PMP, factors affecting its development, and the clinical course of cases with PMP were investigated. Materials and Methods: Twelve thousand and forty-seven cases who underwent appendectomy were reviewed, and 71 mucinous lesions cases whose slides are in our archive were included in the study. Histopathological findings were re-evaluated. Morphological findings that guide the differential diagnosis, the clinical course of the patients, and factors affecting PMP development were determined. Results: The cases were divided into group 1 non-neoplastic (9.9%), group 2 benign (18.3%), group 3 LAMN (60.6), and group 4 malignant neoplasms (11.3%). Age, gender, appendix diameter, gross appearance, epithelial characteristics, and presence of microcalcification were significantly different between the patient groups. The presence of mucin in the ileocecal region was found to be significant in the development of PMP. It was observed that the additional procedure performed after the appendectomy did not prevent a recurrence. Conclusion: LAMNs are lesions with characteristic findings and different behaviors. The only method to distinguish from the lesions included in the differential diagnosis is to interpret the histopathological findings correctly. Additional operations after appendectomy do not contribute to preventing recurrence.
RESUMO
A biópsia por agulha grossa (BAG), ou core biopsy, é uma técnica utilizada para retirar pequenos cilindros de tecido mamário. Além de lesões palpáveis, o desenvolvimento de técnicas radiológicas acuradas de localização de lesões mamárias difundiu o uso da BAG como primeira abordagem histológica de lesões não palpáveis. O diagnóstico diferencial do carcinoma mucinoso com lesões mucinosas benignas por BAG pode ser desafiador, principalmente se a lesão apresentar extravasamento de mucina. A acurácia do diagnóstico nesses casos é de extrema relevância para determinar o tipo de procedimento a ser realizado e o tratamento a ser seguido. Este estudo traz revisão e atualização da literatura sobre carcinoma mucinoso invasor da mama e seus diagnósticos diferenciais, com ênfase nos desafios para diagnóstico por intermédio da BAG. Entre os diagnósticos diferenciais estão alterações fibrocísticas com mucina luminal, lesões mucinosas papilares e mucocele-símile (que variam desde as benignas até aquelas associadas a hiperplasia ductal atípica e carcinoma ductal in situ). Alterações mucinosas também podem ser encontradas em uma variedade de lesões, como fibroadenoma e tumor phyllodes, adenoma pleomórfico e mucinose nodular. Conclui-se que a BAG é uma técnica confiável para diagnóstico de carcinoma mucinoso da mama e seus diagnósticos diferenciais, porém, em casos de dúvida ou de escassez de material, é prudente realizar biópsia excisional para melhor esclarecimento do diagnóstico.
The needle core biopsy is a technique applied to remove small cylinders of breast tissue. The development of accurate radiological techniques for location of breast lesions has spread the use of core biopsy as the first histological approach to non-palpable lesions. The differential diagnosis of mucinous carcinoma and benign mucinous lesions by core biopsy may be challenging, mainly when the lesion shows mucin extravasation. The accuracy of diagnosis in these cases is extremely important to determine the type of procedure to be performed, as well as the treatment choice. This study shows a review and an update of the literature as to invasive mucinous carcinoma of the breast and its differential diagnosis, with emphasis on the challenges of diagnosis by core biopsy. Among the differential diagnoses are fibrocystic changes with luminal mucin, mucinous papillary lesions, mucocele-like lesions that range from benign to those associated with atypical ductal hyperplasia and ductal carcinoma in situ. Mucinous changes may also be found in a variety of lesions such as fibroadenoma, phyllodes tumor, pleomorphic adenoma and nodular mucinosis. In conclusion, core biopsy is a reliable technique for the diagnosis of mucinous carcinoma of the breast and its differential diagnosis, however, in doubtful cases or when the sample is scarce, it is advisable to perform an excisional biopsy to clarify the diagnosis.