Lipophyllodes of the breast. A reappraisal of fat-rich tumors of the breast based on 22 cases integrated by immunohistochemical study, molecular pathology insights, and clinical follow-up.

We have studied 22 cases of mammary lipophyllodes tumors (LPT), analyzing their clinicopathologic features along with available follow-up. All cases were tested for cytokeratins, S100 protein, and MDM2, and in selected cases for estrogen receptor, smooth muscle actin, bcl2, desmin, and myogenin. Patients were women aged 21 to 69 years (average, 45 years), and LPT size ranged from 1.6 to 30 cm (average, 9.7 cm). Microscopically, LPT segregated as follows: atypical lipoma-like tumor/well-differentiated liposarcoma (ALT/WDL), 8 cases; myxoid, 6; and pleomorphic/poorly differentiated/round cell, 8, including a case of dedifferentiated liposarcoma. Immunohistochemistry studies showed focal positive staining for S100 and CD34 in most ALT/WDL, and desmin and myogenin in 2 cases with evidence of rhabdomyoblastic differentiation. MDM2 positivity was focally seen in 1 case. Follow-up was available in 8 cases. Multiple recurrent tumors were seen in 2 patients, and metastatic disease to the lung was seen in 2 patients. In 4 patients with a follow-up between 2 and 15 years there was no evidence of recurrent or metastatic disease. Patients with ALT/WDL (2/2) were alive with no evidence of disease; 2 of 4 patients with myxoid liposarcoma component experienced tumor recurrence, whereas pleomorphic liposarcoma LPT pursued a less favorable course although only 1 patient died of the condition. Absence of MDM2 reactivity in most cases seems not as meaningful as in fatty tumors of somatic soft parts.

Follicular lymphoma in young adults: a clinicopathological and molecular study of 200 patients.

Follicular lymphoma is clinically heterogenous, and therefore necessitates the identification of prognostic markers to stratify risk groups and optimize clinical management. It is relatively rare in patients younger than 40 years, and the clinicopathologic characteristics and biological behavior in this age group are poorly understood. In the current study, samples from a cohort of 200 patients between 19 and 40 years were evaluated retrospectively with respect to clinical, histologic, and genetic features. These were then correlated with clinical outcome. The median age at presentation was 35 years with a slight female prepoderance (56%). Most of the cases are presented with nodal disease (90%). Concomitant follicular lymphoma and diffuse large B-cell lymphoma were observed in 7 (4%) patients. Immunohistologic studies showed the expression of CD10 (91%), BCL6 (97%), BCL2 (95%), MUM1/IRF4 (12%), MDM2 (17%), and CD23 (25%). BCL2 rearrangement was present in 74%, and BCL6 in 20%. The estimated overall survival of patients was 13 years (mean). The presence of anemia, elevated lactose dehydrogenase, bone marrow involvement, and high-risk follicular lymphoma international prognostic index correlated with adverse overall survival. Our findings revealed that follicular lymphoma in young adults demonstrate similarities with that of older adults, including the frequency of presentation at various anatomic sites, grade, and adverse prognostic factors.

Metastatic melanoma presenting as an isolated breast tumor: a study of 20 cases with emphasis on several primary mimickers.

CONTEXT: The mammary gland can be a site of metastasis in patients with malignant melanoma, which is easily recognized microscopically if clinical information is available. Nonetheless, metastatic melanoma presenting as an isolated mammary tumor can be more challenging to diagnose because it can simulate a primary breast carcinoma clinically and morphologically. OBJECTIVE: To review metastatic melanoma to the breast, presenting as primary breast carcinomas clinically and morphologically. DESIGN: The authors report 20 cases of metastatic melanoma clinically presenting as breast tumors. Cases with widespread metastatic presentation were excluded. RESULTS: Epithelioid and spindle cell tumors predominated, suggesting mammary ductal, papillary, or sarcomatoid carcinoma. Most cases (16 of 20) were submitted for consultation or second opinion owing to their unusual presentation in the breast, or to perform predictive/prognostic immunohistochemical assays. Seven cases had a remarkable phenotypic spectrum expanding the differential diagnosis to large cell lymphoma, leiomyosarcoma, medullary carcinoma, malignant schwannoma, and liposarcoma. Tumor cells were negative for cytokeratin stains and positive for S100 protein, HMB-45, and Melan-A. Negative staining was also observed for epithelial membrane antigen, CD45, desmin, estrogen and progesterone receptors, and human epidermal growth factor receptor 2. CONCLUSIONS: Metastatic melanoma may simulate a broad spectrum of primary breast malignancies. Although the application of a simple panel of antibodies assists in rendering the correct interpretation, lesions presenting as isolated breast tumors may introduce a significant diagnostic difficulty, especially when there is inadequate patient history and/or limited biopsy material. Further challenges are introduced by the extraordinary phenotypic plasticity of metastatic melanoma. Awareness of this pattern variance is essential to avoid inappropriate treatment, especially in cases simulating a "triple negative," poorly differentiated carcinoma of the breast.

Immunohistochemistry applied to the differential diagnosis between ductal and lobular carcinoma of the breast.

The distinction between classic lobular and ductal carcinoma, both in situ and invasive, has important therapeutic and management implications. Most ductal and lobular carcinomas are distinguished readily on hematoxylin-eosin-stained sections because of distinct histomorphologic features. In cases with ambiguous morphologic features, however, categorization in one or another type can be a challenge. Several immunohistochemical markers, including epithelial cadherin, p120, ß-catenin, and low-molecular-weight and high-molecular-weight cytokeratins among others, have been introduced to help better discriminate between lobular neoplasia and ductal carcinoma. In this critical review of the literature, we comment about the usefulness and the limitations of these markers to improve the accuracy in the differential diagnosis of breast pathology.

High concordance of SP3 rabbit monoclonal antibody with FISH to evaluate HER2 in breast carcinoma.

HER2 gene amplification or HER2 protein overexpression predicts a more aggressive clinical course in breast cancer, with a worse response to hormonal therapy, and determines eligibility for the use of the anti-HER2 antibody trastuzumab. For these reasons, the diagnostic assays that determine HER2 status in breast carcinoma have become increasingly important. Our goal was to evaluate the concordance, sensitivity, and specificity of a rabbit monoclonal antibody directed to the extracellular domain of the HER2 receptor (SP3) and compare it with fluorescence in situ hybridization and HercepTest in 179 invasive breast carcinomas. We found that SP3 was in agreement with fluorescence in situ hybridization results in 94.6% of cases. HercepTest and fluorescence in situ hybridization results were in agreement in 95.1% of the cases. Only 4.3% (4/93) of the cases that scored 0/1+ by SP3 were amplified by fluorescence in situ hybridization, and 8.3% (3/36) of cases that scored 3+ were not amplified by fluorescence in situ hybridization. Comparing SP3 with HercepTest, we observed that HercepTest demonstrated higher sensitivity (100.0% vs. 89.0%) but SP3 demonstrated higher specificity (97.0% vs. 89.0%). An important advantage of SP3 (in comparison with HercepTest) is its higher discrimination power (72.1% vs. 34.1%). For these reasons, this antibody could be helpful in the determination of HER2 status in a routine basis.