We present the case of a 30‐year‐old lady who underwent a core needle biopsy for a BIRADS 4 lesion of her left breast and was diagnosed as having a cellular fibroadenoma. The final diagnosis after excision returned to be a periductal stromal tumor (PST). An extremely rare entity, the PST is actually classified as a subtype of phyllodes tumor, with specific criteria that are only found upon histological examination of the specimen. Care should be taken when considering the diagnosis of fibroadenoma based only on clinical, radiological, and biopsy findings. Any nonclassical, clinical, or radiological findings should prompt a wide excision. Prognosis is generally good when clear margins are obtained and in the absence of malignant heterologous elements.

RATIONALE: Systemic Seminal Plasma Hypersensitivity (SPH) is caused by specific IgE to human prostate specific antigen (hPSA). Presensitization to dog PSA (Can f 5) was reported to be associated with SPH in women sensitized to dog due to cross-reactivity. Conformational epitope mapping of hPSA is required to elucidate this cross-reactivity and to design hypoallergenic derivatives for desensitization. METHODS: Sequence-and structure-based bioinformatic analyses were performed to identify potential hPSA epitope(s). Sequences of hPSA and other known serine protease allergens were retrieved from the uniprot database. The hPSA structure was obtained from its monoclonal antibodybound form (2ZCH.pdb) to study its antigenic surface and to model the Can f 5 structure. Site-directed mutagenesis of top solvent-exposed residues was performed to assess their role in IgE binding. RESULTS: About 45% (5054.97 A 2) of hPSA surface is polar. Four areas, including a region Arg85-Ser99 (containing the mAb binding site) have been identified as potential epitopes. A close evolutionary relationship between hPSA and Can f 5 (57% sequence identity; 89% sequence similarity) was noted. The alpha-C backbone superimposition (global RMSD51.1 A) indicated an overall structural similarity, while conserved surfaceexposed patches indicated possible cross-reactivity between hPSA and Can f 5. Preliminary results of site-directed mutagenesis indicated the importance of specific surface exposed residues (e.g. R85) in IgE binding. CONCLUSIONS: Epitope residues are dispersed on hPSA surface. Conserved patches might be responsible for cross-reactivity between hPSA and Can f 5 in some patients. Peptide microarray-based epitope mapping and detailed characterization of mutant hPSA proteins are ongoing to confirm these findings.

Junctional ectopic tachycardia (JET) is the most common tachyarrhythmia that appears mostly during the immediate postoperative period of congenital heart surgery. Patients who develop JET have increased mortality and morbidity. Despite the availability of different antiarrhythmic treatments, management of JET is still challenging. We report a case of reversing of malignant JET following congenital heart surgery with the use of oral Ivabradine, after the failure of all the others treatment options of JET. Ivabradine is a drug used in adult practice to lower heart rate in heart failure and angina. Our case report may provide hope that Ivabradine may be a new therapeutic option for JET in infants following congenital heart surgery.