Visualization of Posttraumatic Splenosis on Chemokine Receptor CXCR4-Targeted PET/CT.

The C-X-C motif chemokine receptor 4 (CXCR4) is expressed by a variety of inflammatory and malignant cells. We report the case of a 54-year-old woman with recurrent urinary tract infection who underwent a Ga-pentixafor PET/CT for detection of occult infectious foci. As a secondary finding, multiple CXCR4 abdominal lesions could be seen, consistent with the diagnosis of long-known posttraumatic splenosis. It is important to be aware that CXCR4-directed imaging may identify splenic tissue based on the presence of inflammatory cells and that both benign and malignant cells may show CXCR4 expression to avoid misinterpretation.

Esplenosis: diagnóstico no invasivo de un gran imitador / Splenosis: non-invasive diagnosis of a great mimicker

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Gastric fundus splenosis mimicking stromal tumor

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Experimental splenosis in the liver and lung spread through the vasculature.

To demonstrate that intra-organ splenosis can engraft and develop after being distributed through the vasculature, tiny fragments of splenic tissues were injected into the inferior vena cava or the portal vein to induce intrapulmonary and intrahepatic splenosis in rats. After 1 month, splenic autograft structures in the lung and liver were assessed for structure by histology, for immunologic compartments by immunohistochemistry, for phagocytic function by carbon uptake and for vascular formation by Microfil (a silicon rubber compound) injection. Intrapulmonary and intrahepatic splenoses were indeed able to spread through the vasculature. The intrapulmonary splenic autografts were trapped and spread out in the interstitium, without forming a capsule. White pulp was markedly developed, showing lymphocyte aggregations that consisted in B cells surrounding the dilated vessel. Splenic sinuses were not definitively observed. Although macrophages were detected by immunohistochemistry, they showed no indication of having phagocytized carbon particles from the vessels, implying a closed circulation. In contrast, intrahepatic splenic autografts formed well-developed capsules, trabeculae and red pulp with splenic sinuses. Macrophages detected by immunohistochemistry were observed capturing carbon particles, which clearly revealed an open system circulation, as seen in normal rat spleen. The development of white pulp was poor and lymphocytes consisting in B cells aggregated in the peripheral margins. These results demonstrate that intra-organ splenosis can spread through the vasculature and that the morphologic and immunologic structures formed in these regenerated autografts are influenced by the organ vasculature and extracellular matrix wherein the tissue fragments settled.

Pitfall in follow-up imaging of pancreatic neuroendocrine tumor by somatostatin receptor PET.

56-year old woman was operated of a pancreatic NET in May 2011. Abdominal pain had led to imaging and consecutively the finding of cholecystolithiasis and the tumor. The gall bladder, left hemi-pancreas, regional lymph nodes and the (unintentional injured) spleen were resected. At routine control examination in October 2012 CT presented three contract enhancing intra-abdominal lesions with a diameter of 2-3.5 cm. Consecutively 68Ga-DOTA-NOC PET-CT showed high tracer uptake (SUV 10-12) at these lesions. Therefore a relapse of the neuro-endocrine tumor was suspected. After reoperation in December 2012 histology did not reveal any sign of neuroendocrine tumor but identified spleen tissue most probably caused by splenosis accidentally seeded at the first operation. Physiologically the spleen is highly avid at 68Ga-DOTATOC PET, but splenosis presents with less standard uptake value. In our case the described lesions presented with an SUV quite comparable to that of neuroendocrine tumor tissue.

Intrahepatic splenosis with severe iron deposition presenting with atypical magnetic resonance images.

An intrahepatic mass was incidentally found in a 41-year-old man with a history of a traffic accident injury which resulted in removal of a ruptured spleen. Hepatic splenosis was considered in the differential diagnosis but magnetic resonance imaging showed hypointensity on T2-weighted images, atypical for normal spleen. Histologically, the mass showed sinusoidal structures and lymphoid follicular aggregates. Immunohistochemical study showed that the phenotype of the vascular lining cells was CD8-positive, CD31-positive, and CD34 negative, the pattern diagnostic for ectopic spleen. In addition, severe iron deposition was histologically demonstrated, which was considered as the cause of the hypointense T2-weighted images.

Unusual subcutaneous splenosis occurring in a gunshot wound scar: pathology and immunohistochemical identification.

Splenosis usually occurs after traumatic rupture of the spleen with autotransplantation of splenic tissue to ectopic sites. Most commonly, it occurs as intraperitoneal nodules, which are found either incidentally or after symptomatic complications. Subcutaneous splenosis is a rare condition mostly observed in abdominal surgical scars. Reported herein is a case of subcutaneous splenosis developed in an exit gunshot wound scar on the left lower chest wall 9 years after splenectomy. The lesion presented as an asymptomatic subcutaneous nodule, which was excised under the impression of a skin tumor. Microscopically, there were multiple subcutaneous nodules resembling splenic tissue with red and white pulp. They were confirmed to be ectopic splenic tissue by immunohistochemical staining of the vascular lining cells (CD8+, CD31+, and CD34-). Only 11 cases of subcutaneous splenosis have been reported before. The present case was the third case occurring in an exit gunshot wound scar, and the diagnosis was confirmed by immunohistochemical study.

Extramedullary hematopoietic proliferations, extraosseous plasmacytomas, and ectopic splenic implants (splenosis).

Hematopoietic proliferations are well known to present ectopically outside the bone marrow, either in benign or malignant form. As such, they present a distinct problem with respect to morphologic interpretation because of their uncommonality in extramedullary sites and their capacity to simulate other lesions histologically. This review considers extramedullary myeloid tumors ("granulocytic sarcoma," "erythroblastic sarcoma," "megakaryocytic sarcoma"), tumefactive extramedullary hematopoiesis, and the peculiar condition known as "splenosis," with consideration of their clinical, microscopic, and cytohistochemical chararacteristics.

A unique case of cerebral spleen.

We present the first case of cerebral splenosis, occurring in a 20-year-old man 15 years after posttraumatic splenectomy. He became symptomatic through seizures and was operated on for suspected meningioma of the right occipital pole. Histologic evaluation of the lesion revealed splenic tissue with matching immunohistochemical results. Because no penetrating head injuries were reported at the time of trauma, a hematogenous spread of splenic tissue has to be assumed.

Esquistossomose hepato-esplênica em crianças: corpúsculo de Howell-Jolly após esplenectomia e esplenose / Hepatosplenic schistosomiais mansoni in children: Howell-Jolly bodies after splenectomy and splenosis

A esquistossomose mansônica hepato-esplênica com varizes esofágicas é infrequente em crianças, entretanto, determina morbidade atingindo a produtividade desses futuros adultos. Há evidências de que a esplenose pós-esplenectomia, por trauma, mantém, de forma parcial, as funçSes imunológica e hemocaterética esplênicas. Estudos semelhantes, entretanto, nÝo foram realizados em esquistossomóticos submetidos a esplenectomia. Foram analisados, para avaliaçÝo da funçÝo de esplenose, 15 pacientes, de 7 a 18 anos, com esquistossomose hepato-esplênica submetidos a esplenectomia, ligadura de veia gástrica esquerda e auto-implante esplênico (Grupo A). A esplenose foi comprovada por cintilografia ou por Dopplerfluxometria. Também foram analisados cinco pacientes similares antes da cirurgia (grupo B) e três crianças, nÝo esquistossomóticas submetidas a esplenectomia sem auto-implante esplênico (grupo C). Os esfregaços de sangue periférico foram examinados para pesquisa de corpúsculos de Howell-Jolly, que indicam ausência ou insuficiência de funçÝo hemocaterética esplênica. Dos pacientes do grupo A, um (7por cento) apresentou corpúsculosde Howell-Jolly. Os demais nÝo apresentaram estes corpúsculos (93por cento). Nenhum paciente do grupo B os apresentou, enquanto que todos os esfregaços dos pacientes do Grupo C apresentaram estes corpúsculos. Os dados confirmam o auto-implante esplênico como método edicaz na manutençÝo da funçÝo hemocaterética esplênica