Metaplastic Carcinoma with Extensive Chondroid Differentiation in the Breast (Chondroid Carcinoma)

Metaplastic breast carcinoma is very rare, and metaplastic carcinoma with chondroid differentiation is even rarer. Here, we report a case of metaplastic carcinoma with extensive chondroid differentiation mimicking chondrosarcoma that was challenging to diagnose. The tumor was characterized by an abundant chondromyxoid matrix. The definitive area of classic invasive ductal carcinoma was minimal. The peripheral portion of the tumor showed increased cellularity with pleomorphism and definitive invasive growth. Tumor cells in the chondrosarcomatous areas were diffusely immunoreactive for S-100 protein, patchy positive for cytokeratin, but negative for epithelial membrane antigen (EMA). Tumor cells in carcinomatous areas were diffusely positive for cytokeratin, S-100 protein, and patchy positive for EMA. In both areas, tumor cells were negative for smooth muscle actin (SMA) and CD34, while oncoprotein p53 was overexpressed. When pathologists encounter breast tumors with chondroid differentiation, careful sampling and immunohistochemistry for cytokeratin and SMA are most helpful to differentiate metaplastic carcinoma from malignant phyllodes tumor and malignant adenomyoepithelioma.

Clinicopathologic Features of Granulomatous Mastitis

BACKGROUND: Granulomatous mastitis (GM) is a rare chronic inflammatory condition that clinically mimics a carcinoma. The diagnosis of idiopathic GM depends on the exclusion of other granulomatous inflammations. The purpose of this study is to correlate the clinicopathological features of GM with etiologies. METHODS: We reviewed the clinical records of 58 cases that were histologically diagnosed as GM. We performed special stains for microorganisms such as Ziehl-Neelsen, periodic acid Schiff and gram stains, and polymerase chain reaction (PCR) for Mycobacterium tuberculosis (TB PCR). RESULTS: The mean age of patients was 35.3 years. Most patients were parous except three. Seven patients (12.1%) were related with pregnancy or lactation. TB PCR was positive in nine patients (15.5%). Five patients (8.6%) had gram positive bacilli that were recognizable as coryneform bacteria. Culture study demonstrated Staphylococcus aureus in only one case. Infectious GM had a greater tendency to form abscesses. Fat necrosis was more likely to be present in idiopathic GM, but other histological features were similar to each other. Twenty-two cases (37.9%) showed recurrence. CONCLUSIONS: We suggest that TB PCR and gram stain are essential tests for the differential diagnosis of GM, because the histologic features considerably overlap irrespective of the various etiologies.

Correlation of Heregulin mRNA and Her-2/neu Protein Expression with Node Metastasis and DNA Ploidy Pattern in Human Invasive Breast Carcinoma

The Her-2/neu protooncogene encodes a transmembrane tyrosine kinase that is structurally homologous to the receptor for epidermal growth factor. Its amplification and overexpression are associated with poor prognosis in breast cancer patients. Neu differentiation factor is a ligand for Her-2/neu protooncogene and was detected in ras-transformed rat fibroblasts. Heregulin (human homologue of neu differentiation factor) is a 44-kilodalton glycoprotein that stimulates tyrosine phosphorylation and induces growth arrest or stimulation and differentiation in human breast cancer cell lines. In this study we examined the expression of heregulin mRNA by nested reverse transcription (RT) PCR with fresh tissue, Her-2/neu protein, ICAM-1 and steroid receptors by immunohistochemistry, and DNA ploidy pattern by flow cytometry with paraffin-embedded tissue in invasive breast carcinoma. We compared the data with nodal status, lymphovascular invasion, steroid receptor status and DNA ploidy pattern. For RT-PCR to heregulin mRNA, 38 cases of fresh breast cancer tissue were obtained. Total 68 cases of invasive breast carcinoma tissue were fixed in formalin, which were used for routine histology, immunohistochemistry and flow cytometry. The results are as follows; 1) Heregulin mRNA was expressed in 86.1% of patients with invasive breast carcinoma and 100% of patients with benign breast lesion using nested RT-PCR analysis. 2) Her-2/neu protein was overexpressed in 50.0% of tumors using immunohistochemistry. The expression of Her-2/neu protein was significantly correlated with high counts of lymph nodes with metastasis (p<0.05), and high nuclear grade (p<0.05). 3) Her-2/neu protein overexpression was significantly correlated with a high DNA index(p<0.05). All of the tumors showing Her-2/neu protein overexpression and no heregulin mRNA expression revealed near tetraploid DNA content. However, both Her-2/neu overexpression and heregulin mRNA expressing tumors revealed near tetraploidy in 38.9% and diploidy in 50.0%. Based on these results, heregulin mRNA expression rate was 86.1% in human invasive breast carcinoma. Her-2/neu protein overexpression is associated with high positive lymph node number and DNA index. Statistically significant reverse correlation with lymph node metastasis is not present.