No abstract

INTRODUCCIÓNLa mastocitosis sistémica (MS) es una enfermedad clonal de los progenitores mastocíticos de la médula ósea. El cuadro clínico en la MS varía desde una forma asintomática (indolente) a una forma altamente agresiva con una supervivencia muy corta (leucemia de mastocitos) (1).En 1869, Nettleship describió la urticaria pigmentosa (UP) y en 1887, Unna describió un amento en el número de mastocitos en la UP. Fue ya en 1949, cuando Ellis describió una enfermedad sistémica asociada a hiperplasia de mastocitos.La mayoría de los pacientes afectos son adultos, aunque la enfermedad puede ocurrir a cualquier edad. En función del momento de aparición de los síntomas, en especial, de las [0212-7199 (2008) RESUMENLa mastocitosis es una enfermedad definida por un crecimiento anormal y por la acumulación de mastocitos. En la clasificación de consenso de la OMS del 2001, se distinguió entre procesos bien limitados a piel (mastocitosis cutánea) o bien acumulados a nivel de otros tejidos: médula ósea y/u otros órganos extracutáneos (mastocitosis sistémica) como huesos, hígado, bazo o ganglios linfáticos (70% afectación ósea, con patrón osteolítico u osteoblástico, seguida de 50% de hepatoesplenomegalia).La sintomatología más común en estos enfermos es la afectación de la piel por urticaria pigmentosa (más frecuente en la infancia) o telangiectasia macularis pertans (más frecuente en adultos) donde los mastocitos pueden estar recluidos mucho tiempo, con clínica que proviene de sus mediadores, siendo los niveles de triptasa el reflejo de la carga tumoral. El manejo de esta enfermedad se basa en la administración de tratamiento sintomático con antagonistas de histaminas H1 y H2, así como cromoglicato disódico, necesitando terapia citorreductora sólo en las variantes agresivas de mastocitos sistémica (asociadas a mutación del receptor de tirosin kinasa c-kit D816V) o asociadas a SMP (proliferación de mastocitos e hipereosinofilias asociado a la expresión del gen de fusión FIP1L1-PDGFRA).El interferón tiene un efecto beneficioso sobre los síntomas dermatológicos, hematológicos, gastrointestinales y sistémicos, así como en los esqueléticos, debido a su capacidad de aumentar la densidad ósea y reducir los episodios dolorosos, siendo beneficioso el tratamiento inicial con prednisona.

Up to 3% of adults over 50 years of age show a monoclonal peak values in blood or urine. Findings and prognosis will be distinct in view of the nature of this factor. In B-cell neoplasias (multiple myeloma, Waldeström macroglobulinaemia, chronic myeloid leukaemia and non-Hodgkin lymphoma) the clinical pattern is dominated by the systemic effects produced by the expansion of the malign clone; the monoclonal protein may result in hyperviscosity syndrome or renal damage. On the other hand, there are other less frequent processes called diseases associated to monoclonal components, where the main clinical manifestations and prognosis depend of the biological effects of the monoclonal protein. With reference to this last group, which is the objective of this revision, no bone lesions, anaemia or a greater tendency to infections usually occur when compared with the first group. Even so, there are some cases of interposition between both groups: for instance, type IgM immunoglobulin present in Waldeström macroglobulinaemia may have cold agglutinin activity, and in the case of multiple myeloma, the clone may secrete amyloidogenic light chains.

Lytic and blastic lesions have been associated to malignant tumours, such as solid cancer (breast cancer, renal cancer, prostate cancer, malignant melanoma or thyroid tumours). Although a mixed pattern with lytic and blastic lesions is due to metastatic tumour, this is not the only possible origin. The following case shows a systematic. This case report shows the number of tests that were made in order to discover the origin of osteolytic and osteoblastic lesions and it is notable that there is not an occult neoplasia on every occasion.

Case reportA 78-year-old man with an unremarkable medical history presented to the University Hospital complaining of left arm pain in March 2003. At admission, he was in poor general health but had no fever.Slight pallor of the conjunctiva was observed. The neurological examination was normal and no enlargement of the liver, spleen or lymph nodes was noted.Laboratory tests showed erythrocyte sedimentation rate elevation to 66 mm/h, C-reactive protein level of 12 mg/L, and hemoglobin 10.4 g/L with normal leukocyte and platelet counts. Serum protein electrophoresis disclosed hypoalbuminemia (25 g/L) and hypergammaglobulinemia but showed no monoclonal component. Immunoelectrophoresis, however, detected a faint IgD lambda band in the blood and a homogeneous band of free and bound lambda chains in the urine. Bence Jones proteinuria was found (594 mg/L type lambda). Corrected serum calcium was 8.78 mmol/L. Serum creatinine was elevated to 5.62 mg/dL. The serum total protein was 5.95 g/L, and blood urea nitrogen 149 mg/dL. Serum electrolytes and liver function tests were normal. The total urinary protein for 24 h was 710 mg. Tests were negative for cryoglobulinemia. Serum beta2-microglobulin was 7.65 mg/dL (Table 1). Bone marrow aspirate from the sternum showed 3%-4% of malignant plasma cells. Abdominal fat biopsies were negative for amyloidosis. Plain radiographs disclosed multiple lytic punched-out lesions in right arm. The diagnosis was IgD lambda myeloma with renal failure (stage III of Greipp). The patient was put on melphalan and prednisone chemotherapy. He was administered 8 cycles of treatment until stabilization of his illness, and was in a plateau period taking 11 months. After this time, renal insufficiency and anemia appeared again, with 10% of plasmatic cells in bone marrow. In this moment, the patient was treated with bortezomib for 6 cycles with partial response. Six months after finishing bortezomib, he presented hemoglobin levels of 6.2 g/L, dyspnea and fever. CA125 62.90 UI/mL, and CA15.3 9.90 UI/mL. In bone marrow there were 70% of plasmatic cells. X rays showed new lytic lesions in bone, and right pleural effusion (Fig. 1). Computed tomography of body revealed pleural effusion with thickening of the pleura but no mediastinal or hilar adenopathy were seen. A pleural fluid sample was analyzed and cytopathology was positive for plasma cell neoplasm. Immunofixation study revealed IgG lambda chain restriction with cells positive for CD-138. A biopsy of lesion could not been made because of his family refusing. Grain stain and cultures were negative. He was administered vincristine, liposomal doxorubicin and dexamethasone. Two weeks after the first cycle, pleural effusion had disappeared (Fig. 2), but, after the second cycle the patient was clinically worse and died of toxicity. DiscussionIgD myeloma is an uncommon variant that contributes only 2% of all myelomas. It predominantly affects males and younger than other types of multiple myeloma [1] .There are some typical laboratory findings of IgD multipl...