Clonal X-chromosome inactivation suggests that splenic cord capillary hemangioma is a true neoplasm and not a subtype of splenic hamartoma

What is new in the 5th edition of the World Health Organization classification of mature B and T/NK cell tumors and stromal neoplasms?

The classification of tumors is essential in the diagnosis and clinical management of patients with malignant neoplasms. The World Health Organization (WHO) provides a globally applicable classification scheme of neoplasms and it was updated several times. In this review, we briefly outline the cornerstones of the upcoming 5th edition of the World Health Organization Classification of Haematolymphoid Tumours on lymphoid neoplasms. As is adopted throughout the 5th edition of the WHO classification of tumors of all organ systems, entities are listed by a hierarchical system. For the first time, tumor-like lesions have been included in the classification, and modifications of nomenclature for some entities, revisions of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities are presented along with mesenchymal lesions specific to the stroma of lymph nodes and the spleen. In addition to specific outlines on constitutional and somatic genetic changes associated with given entities, a separate chapter on germline predisposition syndromes related to hematologic neoplasms has been added.

Controversies in the Spleen: Histiocytic, Dendritic, and Stromal Cell Lesions

Histiocytic, dendritic, and stromal cell lesions that occur in the spleen are challenging diagnostically, not well studied due to their rarity, and therefore somewhat controversial. New techniques for obtaining tissue samples also create challenges as splenectomy is no longer common and needle biopsy does not afford the same opportunity for examination of tissue. Characteristic primary splenic histiocytic, dendritic, and stromal cell lesions are presented in this paper with new molecular genetic findings in some entities that help differentiate these lesions from those occurring in non-splenic sites, such as soft tissue, and identify possible molecular markers for diagnosis.

Loss of CTNNB1 exon 3 in sclerosing angiomatoid nodular transformation of the spleen

Sclerosing angiomatoid nodular transformation (SANT) is a rare vascular lesion of the spleen. Although several hypotheses have been suggested, the etiopathogenesis of SANT remains unknown. It is also unclear whether SANT is a reactive or a neoplastic lesion. Since CTNNB1 (β-catenin gene) exon 3 mutations were frequently detected in some rare fibrovascular lesions, we aimed to investigate the presence of oncogenic CTNNB1 mutations in SANT cases. For this purpose, 7 cases of SANT with typical histopathological features were retrieved. First, the presence of CTNNB1 exon 3 alterations was examined with a recently described immunohistochemistry-based method. Then, the findings were confirmed with polymerase chain reaction (PCR), reverse transcription PCR (RT-PCR), and Sanger sequencing. In all cases, immunochemistry of β-catenin gave a staining pattern that was suggestive of exon 3 alteration; however, no missense mutations were found in any case at the CTNNB1 exon 3 hotspot region. Subsequently, we screened for large interstitial deletions of CTNNB1 exon 3 which revealed short PCR products in three cases. Sequencing confirmed that these cases had large interstitial deletions, resulting in loss of the entire exon 3 of CTNNB1. In the remaining four cases, loss of exon 3 was documented at the cDNA level, although genomic deletion was not identified. These results demonstrate that loss of CTNNB1 exon 3 and stabilization of β-catenin with activation of Wnt signaling pathway might have a significant role in the pathogenesis of SANT. Through this study, we provided important evidence for the neoplastic nature and pathogenesis of this disorder.

Imaging features of pathologically proven pediatric splenic masses

Splenic masses present a diagnostic challenge to radiologists and clinicians alike, with a relative paucity of data correlating radiologic findings to pathological diagnosis in the pediatric population. To illustrate splenic mass imaging findings and approximate lesion prevalence, we retrospectively reviewed all splenectomies and splenic biopsies for splenic masses at a single academic pediatric hospital over a 10-year period in patients 18 years and younger. A total of 31 splenic masses were analyzed. Lesion prevalence, pathology and imaging features associated with sampled splenic masses are described. The lesions encountered include benign splenic cysts (9), vascular anomalies (7), hamartoma (3), leukemia/lymphoma (3), granulomata (3) and metastasis (2). We also identified single cases of angiosarcoma, splenic cord capillary hemangioma, congestive hemorrhage, and benign smooth muscle neoplasm.

Vascular neoplasms and non-neoplastic vascular lesions of the spleen

Vascular neoplasms are among the most common conditions affecting the spleen. The majority of these are idiopathic, benign in nature and asymptomatic and therefore treated with a conservative management. Only rare cases cause splenomegaly and/or chronic consumption coagulopathies, thus requiring splenectomy. Among these, the most common is splenic hemangioma, followed by littoral cell angioma and lymphangioma. Peliosis is a peculiar tumor-like non-neoplastic vascular lesion that diffusely affects the spleen and frequently presents with concomitant hepatic involvement. As a distinctive feature, peliosis can occur as a secondary manifestation of infections, malignancies and in individuals using certain drugs. On the opposite spectrum of clinical behavior lies splenic angiosarcoma, a vascular endothelial malignancy with aggressive presentation and poor prognosis. In some cases the endothelial nature of this neoplasm may not be evident on routine histologic examination and immunohistochemistry is used to disclose such phenotype. The term hemangioendothelioma is rarely used to describe borderline vascular neoplasms which appear more aggressive than conventional hemangiomas, but that do not entirely fulfill the diagnostic criteria for angiosarcoma. Some of these neoplasms coexpress endothelial and histiocytic markers and therefore have been proposed as the borderline counterpart of littoral cell angioma. The existence of hemangioendothelioma as a diagnostic entity per se is debated and this diagnosis should be rendered with caution. The current review aims at highlighting the main histologic features of vascular neoplasms and non-neoplastic vascular lesions of the spleen.

A rare case of peliosis hepatis in primary immune deficiency

Peliosis hepatis is a rare condition characterized by blackish-blue blood-filled cavities in hepatic parenchyma caused by dilatation of hepatic sinusoids. Peliosis hepatis has been described in secondary immunodeficiencies and certain medications. We present the first case of peliosis hepatis in a patient with a primary immunodeficiency, common variable immunodeficiency. A 44-year-old African-American male presented with gastrointestinal bleeding and elevated liver function tests. His medical history included common variable immunodeficiency and chronic kidney disease. The patient had jaundice, regenerative nodules on liver pathology, and low immunoglobulin levels. A magnetic resonance imaging of the abdomen with contrast revealed a cirrhotic liver, a 5 × 3 cm lesion, and poorly defined nodules which had decreased enhancement. A computed tomography-guided liver biopsy revealed peliosis hepatis, focal nodular hyperplasia, and fibrosis. No other etiology of his liver disease was found. The etiology of peliosis hepatis in patients with primary immunodeficiencies remains unclear. Additional studies are needed to understand the underlying mechanisms.

Splenic cord capillary hemangioma with non-islet cell tumor hypoglycemia: a case report

Background

Splenic cord capillary hemangioma is a rare benign vascular lesion classified as a splenic hamartoma. On the other hand, non-islet cell tumor hypoglycemia (NICTH) is one of the rare causes of spontaneous hypoglycemia and is considered to be one of the paraneoplastic syndromes. To the best of our knowledge, this is the first reported case of a splenic cord capillary hemangioma with NICTH.

Case presentation

A 25-year-old male was referred to our hospital with hypoglycemia. Except for his low blood sugar, there were no abnormal findings from laboratory tests, which included an endocrinological examination. Enhanced computed tomography confirmed the presence of a solid mass measuring about 6 cm in the retroperitoneum, and a tumorectomy was performed. During this operation, it became clear that the tumor turned out to be a splenic parenchyma, and as a result, a total splenectomy was performed. Microscopically, we diagnosed this as a cord capillary hemangioma, and through immunohistochemistry, we found that some tumor cells were positive for insulin-like growth factor -II. Fortunately, the hypoglycemia-related symptoms disappeared after surgical resection was performed. The patient is still alive and well without evidence of local tumor recurrence 15 years after the operation.

Conclusions

Splenic cord capillary hemangioma, one of the types of splenic hamartomas, is a very rare benign vascular lesion and might be associated with hypoglycemia thought to be NICTH.

Multiclonal tumor origin: Evidence and implications

An accurate understanding of the clonal origins of tumors is critical for designing effective strategies to treat or prevent cancer and for guiding the field of cancer risk assessment. The intent of this review is to summarize evidence of multiclonal tumor origin and, thereby, contest the commonly held assumption of monoclonal tumor origin. This review describes relevant studies of X chromosome inactivation, analyses of tumor heterogeneity using other markers, single cell sequencing, and lineage tracing studies in aggregation chimeras and engineered rodent models. Methods for investigating tumor clonality have an inherent bias against detecting multiclonality. Despite this, multiclonality has been observed within all tumor stages and within 53 different types of tumors. For myeloid tumors, monoclonal tumor origin may be the predominant path to cancer and a monoclonal tumor origin cannot be ruled out for a fraction of other cancer types. Nevertheless, a large body of evidence supports the conclusion that most cancers are multiclonal in origin. Cooperation between different cell types and between clones of cells carrying different genetic and/or epigenetic lesions is discussed, along with how polyclonal tumor origin can be integrated with current perspectives on the genesis of tumors. In order to develop biologically sound and useful approaches to cancer risk assessment and precision medicine, mathematical models of carcinogenesis are needed, which incorporate multiclonal tumor origin and the contributions of spontaneous mutations in conjunction with the selective advantages conferred by particular mutations and combinations of mutations. Adherence to the idea that a growth must develop from a single progenitor cell to be considered neoplastic has outlived its usefulness. Moving forward, explicit examination of tumor clonality, using advanced tools, like lineage tracing models, will provide a strong foundation for future advances in clinical oncology and better training for the next generation of oncologists and pathologists.

CD105 expression in oral capillary hemangiomas and cavernous hemangiomas

Capillary hemangioma (capillary lobular hemangioma) and cavernous hemangioma (venous malformation) are relatively common oral tumors/malformations and are characterized by increased numbers of normal and abnormal blood vessels. However, the causes of these lesions are not well understood. CD105 (endoglin) is predominantly expressed in proliferating blood endothelial cells (ECs). We analyzed expressions of CD105, CD34, von Willebrand factor, Ki-67, cyclooxygenase-2 (COX-2), and vascular endothelial growth factor (VEGF)-A in 31 capillary hemangiomas and 34 cavernous hemangiomas. Staining scores were calculated as the product of the proportion score and intensity score. Morphologically normal oral mucosa specimens (n = 10) were simultaneously evaluated as normal controls. As compared with cavernous hemangiomas and normal controls, capillary hemangiomas had higher staining scores for CD105, VEGF-A, and COX-2. The Ki-67 labeling index was significantly higher in capillary hemangiomas than in cavernous hemangiomas and normal controls (P < 0.01). These findings suggest that the biological characteristics of capillary and cavernous hemangiomas are quite different. The ECs of capillary hemangiomas actively proliferated and were generally regulated by VEGF-A. In contrast, the ECs of cavernous hemangiomas lacked proliferative activity. These results suggest that angiogenesis and vasodilatation of pre-existing blood vessels are important in the development of capillary hemangioma and cavernous hemangioma, respectively.

A case of cord capillary hemangioma of the spleen: a recently proven true neoplasm

Cord capillary hemangioma (CCH) of the spleen is an extremely rare lesion. Once classified under splenic hamartoma, CCH is now differentiated from hamartoma, as its clonality has recently been proven. Herein, we present the case of an incidentally found CCH, measuring 6 × 5.5 × 5 cm, in a 45-year-old man. He underwent splenectomy and has been recurrence-free for 8 years. Macroscopically, the cut surface of the mass showed a central stellate scar with peripheral interspersed reddish areas of variable sizes and intervening fibrous bands. Microscopically, the mass was well demarcated from the splenic tissue. The macroscopic reddish areas were found to correspond to nodules of various sizes, which were predominantly composed of CD34-expressing capillaries without the presence of CD8-expressing sinuses. The relative proportion of these two types of vessels distinguishes CCH from sclerosing angiomatoid nodular transformation (SANT), as SANT shows the apparent presence of CD8-expressing sinuses. In longstanding cases of SANT, sinuses might become ambiguous and the differences between CCH and SANT might become subtle. Nonetheless, immunohistochemistry should be performed when these conditions are suspected, since accurate distinction is usually achieved as a result.