Multiparameter Flow Cytometry Identification of Neoplastic Subclones: A New Biomarker in Monoclonal Gammopathy of Undetermined Significance and Multiple Myeloma.

Multiparameter flow cytometry (MFC)-based clonality assessment is a powerful method of diagnosis and follow-up in monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM). However, the relevance of intraclonal heterogeneity in immunophenotypic studies remains poorly understood. The main objective of this work was to characterize the different immunophenotypic subclones in MGUS and MM patients and to investigate their correlation with disease stages. An 8-color MFC protocol with 17 markers was used to identify the subclones within the neoplastic compartment of 56 MGUS subjects, 151 newly diagnosed MM patients, 30 MM subjects in complete remission with detectable minimal residual disease, and 36 relapsed/refractory MM patients. Two or more clusters were observed in > 85% of MGUS subjects, 75% of stage I MM patients, and < 15% in stage III. Likewise, a significant correlation between the dominant subclone size, secondary cytogenetic features, and changes in the expression of CD27, CD44, and CD81 was detected. The loss of intraclonal equilibrium may be an important factor related with kinetics and risk of progression not well considered to date in MFC studies. The MFC strategy used in this work can provide useful biomarkers in MGUS and MM.

A Rare Case of Pure Erythroid Sarcoma in a Pediatric Patient: Case Report and Literature Review.

We describe an exceptional case of erythroid sarcoma in a pediatric patient as a growing orbital mass with no evidence of morphologic bone marrow involvement, who was finally diagnosed of pure erythroid sarcoma based on histopathology and flow cytometry criteria. We discuss the contribution of standardized eight-color flow cytometry as a rapid and reliable diagnostic method. The use of normal bone marrow databases allowed us to identify small aberrant populations in bone marrow and later confirm the diagnosis in the neoplastic tissue.

[Breast metastasis as initial presentation of a renal carcinoma]. / Metástasis mamaria como manifestación inicial de un carcinoma renal.

OBJECTIVES: To report the case of a breast metastasis as initial presentation of renal carcinoma. METHODS: 72-year-old male patient who consulted for a painful right breast tumor. We describe clinical history, complementary tests, biopsy and treatment. RESULTS: Pathologic study confirmed a metastasis of a renal clear cell carcinoma. A CT scan confirmed the existence of bilateral renal tumors. CONCLUSIONS: Breast metastases are exceptional as initial presentation of a renal carcinoma. We performed a bibliographic review on the topic.

[Merkel cell carcinoma. Study of five cases]. / Carcinoma de células de Merkel. Estudio de cinco casos.

Merkel cell carcinoma (MCC) is a rare malignant skin tumor of neuroendocrine origin with a poor prognosis and rapid progression. It is usually an erythematous nodule on the face, and is associated with other skin neoplasms. Its histology shows a large mass of small cells containing oval nuclei with powdery chromatin in the dermis. These cells are positive for neurospecific enolase, chromogranin, synaptophysin and cytokeratins AE1/AE3. We present five patients (3 males and 2 females, aged 58 to 89 years) seen at our hospital in the last three years for MCC. Their treatment and evolution were tracked, and many of the aspects indicated were seen. MCC must be kept in mind in the differential diagnosis, as early detection along with aggressive treatment significantly improve the patients survival rate. Close follow up is necessary because of the high recurrence rates. The development of a response protocol in order to better manage this disease would be desirable.