Giant Borderline Phyllodes Tumor Fungating Through the Skin as Fleshy Polypoid Outgrowths.

We present the case of a 52-year-old female with a giant phyllodes tumor (GPT), which was fungating through the skin that showed fleshy polypoid outgrowths. Histological analysis revealed stromal atypia, mitotic activity, and stromal overgrowth; however, the tumor border was well-defined, and malignant heterologous elements were not observed. Therefore, as some but not all malignant histological characteristics were present, we diagnosed the patient with borderline GPT. In cases of phyllodes tumor (PT) with the unique gross findings of fungation through the skin as fleshy polypoid outgrowths, caution is required for the subsequent course because even if the PT is graded as benign histologically, a malignant process can occur. Pathologists should note that the sampling of the collection site and the ambiguity of the histological grading of PT may affect the final diagnosis of GPT. It is also important to perform surgery with adequate preservation of the resected margins to control recurrence for patients with GPT.

A Unique Surgical Case of Mixed Metaplastic Breast Carcinoma With Heterologous Mesenchymal Differentiation and Conventional Adenocarcinomatous Elements.

Metaplastic breast carcinoma (MBC) is very rare among all invasive breast carcinomas, accounting for less than 1.0% of them. MBCs are classified into five subtypes, including mixed MBC - where the mix might be multiple metaplastic elements or a mixture of epithelial and mesenchymal elements. Overall survival for mixed MBC tends to correlate with a significantly worse outcome. Therefore, an early accurate diagnosis and surgical treatment for mixed MBCs must allow for an improved quality of life and better prognosis. However, there have not been many recently published papers describing the detailed cytological features of mixed MBCs on fine-needle aspiration (FNA) specimens. A 60-year-old female presented with a history of a hard breast mass on the left lateral side, showing an ill-defined and marginally enhanced tumor nodule on magnetic resonance imaging. The cytologic specimens of FNA contained a large number of three-dimensional, cohesive and sheet-like clusters, or non-cohesive single cells, of highly atypical spindled sarcomatoid to oval epithelioid cells having hyperchromatic pleomorphic nuclei and mitotic figures, in a necrotic and hemorrhagic background. A small amount of osteoid matrix-like substance was rarely seen, associated with a very small number of osteoclast-like giant cells. We first interpreted it as an invasive breast carcinoma of high grade. A mastectomy was performed, and a gross examination of the neoplasm revealed a hemorrhagic solid tumor lesion with a gray-whitish cut surface, measuring approximately 35 × 24 × 21 mm in diameter. On a microscopic examination, the tumor was predominantly composed of the proliferation of highly atypical oval to spindled cells predominantly in a sarcomatous growth fashion with focal production of chondroid and osteoid matrix, peripherally coexisted with a smaller volume of conventional invasive breast carcinoma. Immunohistochemistry showed that the sarcomatous tumor cells were specifically positive for vimentin, α-smooth muscle actin, or epithelial membrane antigen. Therefore, we finally made a diagnosis of invasive mixed MBC with heterologous mesenchymal differentiation and conventional adenocarcinomatous elements. To the best of our knowledge, this would most recently be the first case report of mixed MBC with heterologous mesenchymal differentiation and conventional adenocarcinomatous elements, with a focus on its FNA cytomorphologic findings. We should be aware that owing to its characteristic cytological features, cytopathologists might be able to make a correct diagnosis of MBC, based on multiple and adequate samplings.

Periarterial or perivenous invasion is an independent indicator of lymph node metastasis in invasive breast carcinoma of no special type.

Pathological diagnosis of breast cancer often includes cases of lymph node metastases without lymphatic or lymphovascular invasion by the primary tumor. In this study, to resolve this discrepancy, we designed a sensitive method to detect lymphatic invasion and correlate it with lymph node metastasis. Elastica van Gieson (EVG) staining and D2-40 immunohistochemistry revealed the abundant distribution of lymphatic vessels around blood vessels in the mammary tissue in close proximity to the elastic fibers around the arteries and veins. Based on the histological location of the blood and lymphatic vessels, we hypothesized that, in breast cancer, perivascular invasion is similar to lymphatic invasion and correlates with the presence of lymph node metastasis. Using EVG staining, perivascular invasion was histologically classified into periarterial invasion (periA), perivenous invasion (periV), and periarterial or perivenous invasion (periA/V). We tested our method and compared it to other methods commonly used for identifying lymphatic invasion in 105 patients with invasive breast carcinoma of no special type (IBC-NST) who received minimal preoperative therapy. The correlation between perivascular invasion and lymph node metastasis in these patients was statistically analyzed, including findings related to lymphatic invasion, such as retractile artifacts and perineural invasion. PeriA, periV, and periA/V showed significant correlations with lymph node metastasis. PeriA/V had high sensitivity and negative predictive value. The odds ratio (OR) for periV was significantly high in the univariate analysis, while the ORs for periA/V, retraction artifacts, and perineural invasion were significantly high in both the univariate and multivariate analyses. In particular, periA/V revealed a strong correlation with lymph node metastasis (OR: 61.8). These findings indicate that the IBC-NST periA/V ratio is a sensitive pointer of lymphatic invasion and could be an independent and reliable indicator of lymph node metastasis.