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Abstract: A 59-year-old woman with newly diagnosed pulmonary nodules underwent both 18F-FDG and 68Ga-FAPI PET/CT. Both studies showed similarly increased uptake in pneumonia. However, only 68Ga-FAPI PET/CT showed increased uptake in splenic hemangioma, whereas FDG uptake in the splenic lesion is low. Our case illustrates that splenic hemangioma can also reveal increased FAPI activity., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

The behavior of littoral cell neoplasms ranges from benign (littoral cell angioma, LCA) to highly malignant (angiosarcoma). Two unusual cases of low-grade metastatic littoral cell angiosarcoma (LCAS) have been reported with late recurrence and bulky metastases. We present the third case of this rare neoplasm in a 38-year-old man with cirrhosis and a large splenic artery aneurysm, without extrasplenic masses. The spleen showed nodules resembling LCA, immunoreactive for CD31, factor VIII, CD68, and CD163 but not CD8 or CD34. Also present were solid areas of immunophenotypically identical bland spindle cells, although lighter CD31 immunostaining distinguished them from LCA-like angiomatous channels. Similar cells diffusely infiltrated the cirrhotic liver. After splenectomy, pancytopenia resolved, and he is asymptomatic 19 months later. Low-grade LCAS is a previously unreported cause of cirrhosis and may metastasize without forming masses. In cases of LCA, CD31 immunohistochemistry may facilitate detection of LCAS and indicate metastatic potential.

This report describes the microscopical and immunohistochemical characteristics of littoral cell angiosarcoma in a 12-year-old, neutered female, beagle dog. The dog succumbed to metastatic disease 3 months after diagnosis of a mid-splenic mass. The tumour was characterized by two histological patterns: anastomosing microvascular channels and microvascular papillary fronds. The neoplastic cells expressed both endothelial and histiocytic markers and were erythrophagocytic. Immunohistochemical findings consistent with malignancy were CD34 expression and high Ki67 nuclear immunoreactivity., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Littoral cell angioma (LCA) is a rare vascular tumor of the spleen. Generally thought to be benign, additional cases of LCA with malignant features have been described. Thus, its malignant potential seems to vary and must be considered uncertain. The etiology remains unclear, but an immune dysregulation for the apparent association with malignancies of visceral organs or immune-mediated diseases has been proposed., Case Presentation: We report a case of LCA in a 43-year old male patient who presented with a loss of appetite and intermittent upper abdominal pain. Computed tomography showed multiple hypoattenuating splenic lesions which were hyperechogenic on abdominal ultrasound. Lymphoma was presumed and splenectomy was performed. Pathological evaluation revealed LCA., Conclusions: LCA is a rare, primary vascular neoplasm of the spleen that might etiologically be associated with immune dysregulation. In addition, it shows a striking association with synchronous or prior malignancies. With about one-third of the reported cases to date being co-existent with malignancies of visceral organs or immune-mediated diseases, this advocates for close follow-ups in all patients diagnosed with LCA. To our knowledge, this report is the first one of LCA associated with previous pulmonary sarcoidosis and hypothesizes a TNF-α related pathogenesis of this splenic tumor.

Littoral cell angiomas are uncommon primary vascular neoplasms that arise from the sinusoidal lining or littoral cells of the splenic red pulp, and hence are unique to the spleen. We report a case of littoral cell angioma in 34-year-old woman, which was diagnosed by endoscopic ultrasound-guided fine needle aspiration biopsy (EUS-FNAB). The cytologic features of littoral cell angiomas have been described only in three previous case reports, one of which was a bench-top aspirate. In our case, we have utilized the fine-needle aspiration samples obtained by a linear endoscopic ultrasound examination for establishing the diagnosis. The characteristic cytologic features identified on the smears along with immunohistochemical analysis performed on the compact cellblock prepared from the aspirate aided in the confirmation of the diagnosis. We suggest that EUS-FNAB is a safe and reliable method in the diagnosis of vascular lesions of the spleen., (Copyright © 2010 Wiley-Liss, Inc.)

The authors describe 3 cases of sclerosing angiomatoid nodular transformation (SANT) of the spleen diagnosed at Memorial Sloan-Kettering Cancer Center within a 1-year period (July 2008 to June 2009). All patients were female, older than 50, with lesions ranging in size from 2 to 4 cm. All were alive and well after splenectomy. All the cases showed characteristic histological and immunophenotypical findings as previously described in the literature, including scattered IgG4positive plasma cells in the fibrosclerotic stroma. Of the 3 patients, 2 had a history of carcinoma, and metastasis was of concern, but a PET scan in one of these patients showed minimal to absent FDG activity suggesting that this process was of a benign indolent nature. However, in 1 patient, a PET scan revealed positive FDG activity, heightening clinical concern for malignancy.

Sclerosing angiomatoid transformation of the spleen (SANT) is a relatively new, rare, and unique lesion that involves the spleen. Less than 30 cases have been described to date. The lesion commonly affects middle-aged adults and shows a female predilection. It is often discovered incidentally through imaging. SANT is morphologically and immunohistochemically distinct. However, as it is a relatively new entity, misdiagnosis of SANT may lead to overtreatment of the patients. The pathogenesis of SANT is unknown. The lesion is entirely benign, and splenectomy is curative. We report a new case of SANT, with emphasis on the differential diagnosis and pathogenesis of SANT.

Vascular benign lesions are the most common non-hematological splenic primary tumors. Although rare they may sometimes pose problems in differential diagnosis, because of their morphologic heterogeneity. We present vascular lesions of the spleen, which were found in archive of the Chair of Pathomorphology. Immunohistochemistry including CD34, CD31, factor VIII, CD8, CD21, CD68, lysosyme, GLUT-1, D2-40, VEGFR3, SMA, Ki67 were performed. 8 benign vascular lesions were identified, including two hamartomas, two lesions representing sclerosing angiomatoid nodular transformation (SANT) and four hemangiomas. We present briefly the spectrum of vascular lesions occurring in the spleen and discuss differential diagnosis and nosological status of selected lesions.

Twenty-five cases of a morphologically distinctive vascular lesion of the spleen are described. The patients were 17 women and 8 men, ranging in age from 22 to 74 years (mean, 48.4 years; median, 56 years). The most common presentations were incidental finding of an asymptomatic splenic mass (13 patients), abdominal pain or discomfort (6 patients), and splenomegaly (4 patients). None of the patients had evidence of recurrent disease after splenectomy. The splenic lesion was solitary, measuring 3 to 17 cm, and sharply demarcated from the surrounding parenchyma. The cut surface revealed a mass of coalescing red-brown nodules embedded in a dense fibrous stroma. All cases showed a remarkably consistent multinodular appearance at low-power examination. The individual nodules had an angiomatoid appearance, in the sense that they were composed of slit-like, round or irregular-shaped vascular spaces lined by plump endothelial cells and interspersed by a population of spindly or ovoid cells. Some of the nodules (particularly the smaller ones) were surrounded by concentric rings of collagen fibers. Numerous red blood cells were present, as well as scattered inflammatory cells. Nuclear atypia was minimal, mitotic figures were extremely rare, and necrosis was consistently absent. The internodular stroma consisted of variably myxoid to dense fibrous tissue with scattered plump myofibroblasts, plasma cells, lymphocytes, and siderophages. Immunostaining revealed 3 distinct types of vessels in the angiomatoid nodules: CD34+/CD8-/CD31+ capillaries, CD34-/CD8+/CD31+ sinusoids, and CD34-/CD8-/CD31+ small veins, recapitulating the composition of the normal splenic red pulp. These features are therefore different from those of littoral cell angioma, conventional hemangioma, and hemangioendothelioma of the spleen. We interpret these angiomatoid nodules as altered red pulp tissue that had been entrapped by a nonneoplastic stromal proliferative process. The characteristic morphologic appearance, immunophenotype, and benign clinical course suggest that this is a distinctive nonneoplastic vascular lesion of the spleen that we propose to designate as sclerosing angiomatoid nodular transformation (SANT).

Aims: Diffuse haemangiomatosis of the spleen is a rare benign vascular condition occurring as a manifestation of systemic angiomatosis or, less commonly, confined to the spleen. It is sometimes accompanied by severe disturbance of blood coagulation. The goal of this study was to characterize an additional case of isolated diffuse haemangiomatosis of the spleen and to determine the histogenesis of this lesion which remains obscure., Methods and Results: We describe a case of isolated diffuse haemangiomatosis of the spleen in which histological and immunohistological findings suggested the possibility of a malformative tumour-like lesion. The pathological cavernous vessels were distributed randomly through the red pulp, without continuity with sinuses. The endothelial cells expressed vimentin, factor VIII related antigen and CD34, but not CD8. Some cells lining the sinus lumen expressed CD68, lysozyme and myeloperoxidase. In addition, trabecular veins presented with intimal thickening. These results allow making a diagnosis between diffuse haemangiomatosis and other tumours/tumour-like lesions of the spleen, especially littoral cell angioma, splenoma and peliosis., Conclusion: If diffuse haemangiomatosis is usually classified as a benign proliferation of endothelial cells, we suggest that diffuse haemangiomatosis, when confined to the spleen, could be a tumour-like vascular lesion. In this hypothesis, the aetiology may be hamartomatous or malformative as is suspected in arterio-venous haemangioma of the lower extremities. The histogenesis is still questionable and no definitive proof in favour of one or the other hypothesis has been reported.