A clinicopathological study of fibroadenomas with epithelial proliferation including lobular carcinoma in-situ, atypical ductal hyperplasia, DCIS and invasive carcinoma.

BACKGROUND: Fibroadenoma is a benign mixed tumor composed of epithelial and non-epithelial components. The epithelial component of a fibroadenoma may exhibit proliferation, including lobular carcinoma in-situ, atypical ductal hyperplasia, DCIS and rarely, invasive breast carcinoma. OBJECTIVE: In this series of 30 cases of fibroadenoma with epithelial proliferation, we assessed the radiological and histopathological findings of each entity. METHOD: A retrospective review was performed to identify all fibroadenomas diagnosed at our institution between January 2012 and May 2018. RESULTS: In a total of 1523 consecutive cases of fibroadenomas, thirty cases had epithelial proliferations with an overall prevalence of 1.97%. Eight cases had fibroadenoma with lobular carcinoma in-situ, six cases had atypical ductal hyperplasia, ten cases had DCIS and six cases had invasive carcinoma. In cases of fibroadenomas with lobular carcinoma in-situ, 62.5% of the cases the neoplasia was confined to the fibroadenoma whereas only 10% of the cases with DCIS showed confinement to the fibroadenoma (p = 0.036). The most common radiological finding was the presence of a mass. The BI-RADS scores were 4 and above in all cases (p > 0.05). CONCLUSION: In our study population, the most common type of carcinoma arising in fibroadenomas was DCIS, followed by lobular carcinoma in-situ. Lobular carcinoma in-situ was more likely to be confined to the fibroadenoma while most DCIS involved surrounding breast tissue.

Ontogenesis of myosin light chain phosphorylation in guinea pig tracheal smooth muscle.

Increased airway responsiveness occurs in normal young individuals compared to adults. A maturation of airway smooth muscle (ASM) contractility is likely a mechanism of this juvenile airway hyperresponsiveness. Indeed, we showed in guinea pig tracheal smooth muscle (TSM) that maximum shortening velocity decreases dramatically after the first 3 weeks of life. Because the phosphorylation of the 20-kDa myosin light chain (MLC(20)) was shown to be a key event in ASM contractility, in the present work we sought to investigate it during ontogenesis. In three age groups (1-week-old, 3-week-old, and adult guinea pigs), we assessed the amount of MLC(20) phosphorylation achieved either in TSM crude protein homogenates exposed to Mg(2+) . ATP . CaCl(2) or in tracheal strips during electrical field stimulation (EFS). Phosphorylated and unphosphorylated MLC(20) were separated on nondenaturing 10% polyacrylamide gels, and the ratio of phosphorylation was obtained by densitometric analysis of chemiluminescent Western immunoblots. Maximum MLC(20) phosphorylation (% of total MLC(20)) in TSM tissue homogenate was, respectively, 32.6 +/- 5.7, 32.2 +/- 5.7, and 46.8 +/- 5.8 in 1-week, 3-week, and adult guinea pigs. Interestingly, in nonstimulated intact tracheal strips, we found a substantial degree of MLC(20) phosphorylation: respectively, 42.2 +/- 5.8, 36.5 +/- 7.8, and 46.4 +/- 4.7 in 1-week, 3-week, and adult guinea pigs. Maximal EFS-induced MLC(20) phosphorylation (% increase over baseline) in the 3-week age group was attained after 3 sec of EFS, and was 161.2 +/- 17.6, while in 1-week and adult guinea pigs, it was attained at 1.5 sec of EFS and was, respectively, 133.3 +/- 9.3 and 110.2 +/- 3.9 (P < 0.05). We conclude that MLC(20) phosphorylation in guinea pig intact tracheal strips correlates with ontogenetic changes in shortening velocity and changes in myosin light chain kinase content. These results further suggest that the maturation of ASM contractile properties plays a role in the greater airway responsiveness reported in children and young animals.