Littoral cell angioma of the spleen: a study of 25 cases with confirmation of frequent association with visceral malignancies

Stroma-derived neoplasms and pseudoneoplastic lesions of the spleen: a select review of pathologic and CT/MRI findings

A wide spectrum of benign and malignant primary mesenchymal tumors and tumor-like lesions of the spleen has been recently included under the umbrella term 'stroma-derived' neoplasms and tumor-like lesions. These include dendritic cell neoplasms such as follicular dendritic cell sarcoma, EBV-positive inflammatory follicular dendritic cell sarcoma, and fibroblastic reticular cell tumor; smooth muscle and myofibroblastic lesions such as inflammatory pseudotumor, EBV-associated smooth muscle tumor and undifferentiated pleomorphic sarcoma as well as a diverse spectrum of vascular and vascular-stromal tumors and tumor-like lesions. While some tumor and tumor-like lesions are unique to the spleen, others may also occur in diverse extra-splenic viscera. These tumors and tumor-like lesions demonstrate characteristic histopathology, immunocytochemistry and biological behavior. While cross-sectional imaging studies allow detection, staging and limited characterization of these splenic lesions, histopathological confirmation permits optimal management and surveillance strategies.

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.

Littoral cell angioma of the spleen: A study of 10 cases case series and literature review

BACKGROUND

Current study aimed to investigate the clinical characterization, differential diagnosis, and treatment of splenic littoral cell angioma (LCA).

METHODS

A retrospective analysis was performed for 10 LCA cases admitted to Huzhou Central Hospital from 2007 to 2023, for clinical manifestations, hematological tests, imaging features, pathological features, treatment methods, and prognosis along with the relevant literature was also reviewed.

RESULTS

During examinations, no specific clinical manifestations and hematological abnormalities were seen in all 10 cases of LCA. Imaging observations depicted single or even multiple spherical lesions in the spleen. Plains shown by computed tomography (CT) were found somewhat equal or slightly lower in density. On the other hand, magnetic resonance imaging (MRI) plain scans viz. T1 weighted image showed equal low and mixed signals while T2-weighted showed high and low mixed signals. Moreover, punctate low signals could be seen in high signals named "freckle sign" in MRI scans. On contrast-enhanced CT scans, the enhancement of the lesions was not obvious in the arterial phase, and some of the lesions showed edged ring-like enhancements and "filling lake" progressive enhancement during the venous phase and delayed phase. In multiple lesions, the number of enhanced scan lesions showed a variable changing pattern "less-more-less." MRI-enhanced scan showed the characteristics of "fast in and slow out." Microscopic examinations identified tumor tissue actually composed of sinus-like lacunae that anastomosed with each other in the form of a network. Furthermore, cystic expansion and pseudopapillary protrusions were also seen in the dilated sinus cavity which was lined with single-layer endothelial cells having conspicuous cytoplasmic hemosiderin. High immunophenotypic expressions of vascular endothelial cell phenotype (CD31, CD34, FVIII) and tissue cell phenotype (CD68) were also seen. Total and partial splenectomy were performed in 8 and 2 patients, respectively, and follow-up examinations showed survival in all patients with no recurrence.

CONCLUSION

LCA is a rare splenic benign lesion with atypical clinical manifestations. CT and MRI imaging are important tools in preoperative diagnosis based on pathomorphological and immunohistochemical examinations. Splenectomy is a superior therapeutic choice with significant impacts and prognosis.

Littoral cell angioma of the spleen: case report and literature review

Littoral cell angioma is an extremely rare splenic vascular tumor originating from the cells lining the splenic red pulp sinuses. Approximately 150 cases of littoral cell angioma have been reported since 1991. Its clinical manifestation is usually asymptomatic and is mostly diagnosed as an incidental finding through abdominal imaging. Herein, we present a case of littoral cell angioma in a 41-year-old woman with no previous comorbidities, which initially presented as a nonspecific splenic lesion diagnosed on imaging in the emergency room. The patient was treated through laparoscopic intervention.

Littoral Cell Angioma of the Spleen: A Case Report

Littoral cell angioma (LCA) is a rare, primary vascular tumor of the spleen that originates from the cells lining the venous sinuses of the spleen. Around 150 cases have been reported worldwide, with most reported cases of LCA being non-malignant but with unspecified malignant potential. As of 2022, three cases of malignant LCA have been reported. A 75-year-old male with a history of monoclonal gammopathy of uncertain significance presented with left upper outer quadrant abdominal pain. Ultrasound (US) scan showed a 10.5 cm round, circumscribed mass lesion, with hyperechoic foci, occupying the posterolateral aspect of the spleen. US-guided core needle biopsy of the mass revealed a diagnosis of "atypical cells present, suggestive of vascular neoplasm of the spleen," which was based on histologic and immunohistochemistry characteristics. Due to the size of the lesion, a malignant neoplasm was suspected, and a splenectomy was performed. Histological and immunohistochemical features of the splenic lesion returned a final diagnosis of benign LCA.

Early postsurgical lethal outcome due to splenic littoral cell angioma: A case report

BACKGROUND

Littoral cell angioma (LCA) is a rare benign vascular tumor of the spleen. Given its rarity, standard diagnostic and therapeutic recommendations have yet to be developed for reported cases. Splenectomy is the only method of obtaining a pathological diagnosis and providing treatment to obtain a favorable prognosis.

CASE SUMMARY

A 33-year-old female presented with abdominal pain for one month. Computed tomography and ultrasound revealed splenomegaly with multiple lesions and two accessory spleens. The patient underwent laparoscopic total splenectomy and accessory splenectomy, and splenic LCA was confirmed by pathology. Four months after surgery, the patient presented with acute liver failure, was readmitted, rapidly progressed to multiple organ dysfunction syndrome and died.

CONCLUSION

Preoperative diagnosis of LCA is challenging. We systematically reviewed online databases to identify the relevant literature and found a close relationship between malignancy and immunodysregulation. When a patient suffers from both splenic tumors and malignancy or immune-related disease, LCA is possible. Due to potential malignancy, total splenectomy (including accessory spleen) and regular follow-up after surgery are recommended. If LCA is diagnosed after surgery, a comprehensive postoperative examination is needed.

Laparoscopic management of benign splenic tumors in children

Background

The splenic tumor is relatively rare in children. However, diagnosing and managing this disease remain controversial. This study aimed to evaluate the clinical characteristics and pathological features of benign splenic tumors and to explore the feasibility and safety of laparoscopic splenectomy in children.

Methods

The clinical data of all patients who were diagnosed with benign splenic tumors and admitted to our center between January 2014 and December 2020 were analyzed retrospectively. Factors that were documented included demographic criteria, clinical manifestations, preoperative examinations, surgical methods, histopathological characteristics, postoperative complications and outcomes.

Results

Totally, 24 consecutive patients with a mean age of 10.21±2.59 years were operated laparoscopically. Nine patients presented with recurrent abdominal pain, vomiting or backache. The remaining 15 cases were asymptomatic and were identified incidentally. Laparoscopic total splenectomy (LTS) was performed in 12 cases, laparoscopic partial splenectomy (LPS) in 9 cases and deroofing of splenic cyst in 3 cases. No significant differences were observed in operation time, intraoperative bleeding and postoperative abdominal drainage between the LTS and LPS groups. Histopathology examination reported 12 cases of splenic epithelial cyst, 5 cases of splenic lymphangioma or lymphatic malformation, 3 cases of splenic hamartoma, 3 cases of splenic littoral cell angioma and 1 case of splenic hemangioma. No postoperative complications and tumor recurrence were observed.

Conclusions

It is still difficult to precisely diagnose the splenic tumor preoperatively. Laparoscopic splenectomy is safe and feasible in treating the benign splenic tumors, and partial splenectomy is of great significance in preserving the immune function in children.

Case Report: Complete Remission With Anti-PD-1 and Anti-VEGF Combined Therapy of a Patient With Metastatic Primary Splenic Angiosarcoma

Primary splenic angiosarcoma (PSA) is a rare malignancy with poor prognosis. At present, little study is available on immunotherapy in PSA. Here, we report a case of a patient with metastatic PSA who was treated with programmed death-1 (PD-1) inhibitors and vascular endothelial growth factor (VEGF) tyrosine kinase inhibitors combined therapy and achieved complete response (CR). The patient was a 57−year−old woman with three liver metastases. She was treated with seven cycles of toripalimab plus anlotinib. Programmed death-ligand 1 (PD-L1) immunohistochemistry and next-generation sequencing was performed, and the PD-L1 tumor proportion score was 75%. Finally, she achieved CR after six cycles of the combined therapy regimen. No serious adverse events were detected. To the best of our knowledge, this is the first clinical evidence that anti-PD-1 plus anti-VEGF therapy might be a promising option for patients with metastatic PSA. However, more clinical trials are needed to verify this conclusion.

Clinical Landscape of Littoral Cell Angioma in the Spleen Based on a Comprehensive Analysis

Objective

Littoral cell angioma (LCA) is currently considered to be a rare splenic tumor with malignant potential. As the epidemiology, pathogenesis, clinical manifestation, treatment, and prognosis remain unclear, the clinical diagnosis and treatment of LCA have not been standardized. Hence, we performed a comprehensive analysis of 189 observational studies comprising 435 patients to improve the current status of diagnosis and treatment.

Methods

PubMed, Embase, WanFang and CNKI were searched from inception to May 2021 to identify LCA studies that were published in English and Chinese. The clinical information of LCA patients were extracted and analyzed.

Results

The LCA has a male-to-female ratio of 0.90 and a solitary-to-multiple ratio of 0.31. In terms of clinical features, 69.7% of the patients showed splenomegaly, 49.7% were asymptomatic, and 39.2% experienced epigastric discomfort. As the imaging findings of patients with LCA were nonspecific, an image-guided biopsy (10/12) was a safe and effective method for diagnosing in this condition. Notably, results of the prognostic analysis indicated that LCA has a lower risk of recurrence and metastasis. The patient may develop a stable disease or the tumor will grow but will not metastasize. Besides, the novel immunohistochemical pattern of LCA was described as CD31⁺/ERG⁺/FVIII Antigen⁺/CD68⁺/CD163⁺/lysozyme⁺/CD8⁻/WT1⁻.

Conclusion

LCA should be reconsidered as a benign primary splenic vascular neoplasm, which is more like an intra-splenic manifestation of abnormal body function. Image-guided biopsy with follow-up might be a beneficial choice for LCA patients. For LCA patients with abdominal discomfort, pathological uncertainty or continuous tumor enlargement, splenectomy remains the preferred treatment.

Rare case of littoral cell angioma recognised on CT simulation for adjuvant radiation treatment for early stage breast cancer

A 63-year-old woman with pathological anatomic/prognostic stage IA ER+/PR+/HER2- multifocal invasive mammary carcinoma with mixed ductal and lobular features of the left breast underwent lumpectomy with sentinel lymph node biopsy. During evaluation of the CT simulation for adjuvant radiation (RT) treatment planning, a liver lesion and splenomegaly were noted. A subsequent MRI abdomen revealed a large, indeterminate splenic lesion with a wide differential and a benign liver cyst. The patient ultimately underwent splenectomy, with pathology consistent with littoral cell angioma, a rare entity associated with several malignancies. At last follow-up, 7 months after completion of RT, she remained cancer free while on anastrazole and was doing well clinically.

A rare vascular tumor of the spleen: Littoral cell angioma

INTRODUCTION

Being a rare benign vascular tumor of the spleen, Littoral cell angioma involves multiple focal nodules in the spleen and splenectomy is used for both definitive diagnosis and treatment.

PATIENTS AND METHODS

A 30-year-old male patient presented to our clinic with the complaints of intermittent abdominal pain and fever. In physical examination, splenomegaly was found and he was further evaluated with ultrasonography, tomography and magnetic resonance imaging that have revealed multiple solid mass lesions of various sizes in his spleen. The patient was administered open splenectomy and recovered uneventful.

RESULTS

After histopathological and immunohistochemical analyses of the splenectomy material, he was diagnosed with Littoral cell angioma.

CONCLUSIONS

For a timely diagnosis, Littoral cell angioma should be considered among the initial diagnoses in patients who were found to have splenomegaly in their physical examination and multiple masses in the spleen in radiological tests.

Case report: Infrequent littoral cell angioma of the spleen

Introduction and importance

Littoral cell angioma is a rare solid spleen tumor with uncertain malignant potential. It is usually asymptomatic; therefore, its diagnosis is usually incidental. There are approximately 150 cases reported in the medical literature, but none of them in the Hispanic population.

Case presentation

We present a case of a 54-year-old woman who presented to our clinic with nonspecific abdominal pain. Imaging studies show a splenic mass with littoral cell angioma characteristics. The patient underwent an open splenectomy with subsequent histopathologic and immunohistochemical studies that confirmed the presence of a littoral cell angioma of a diameter of 8 × 4.5 × 3.5 cm. The patient was discharged after an uneventful postoperative recovery and was referred to the outpatient clinic for follow up.

Clinical discussion

This case report highlights the close relationship between the littoral cell angioma, neoplasias, and autoimmune diseases. Even though LCA has a good prognosis, there is still the possibility of malignant transformation, especially when the spleen weighs 1500 g; our patient's sample pointed towards a benign pathology. LCA has a positive IHC for endothelial and histiocyte tissues. The IHC results of our patient were positive for CD34⁺ and CD68⁺, confirming the LCA diagnosis.

Conclusion

Within red pulp spleen tumors, LCA should be highly considered as a differential diagnosis in all types of populations. In the case of a confirmed LCA, routine screening for neoplasias and autoimmune diseases should be performed.

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LCA is a benign tumor with endothelial and histiocytic differentiation.

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LCA has a close relationship with neoplasias and autoimmune diseases.

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LCA is more prevalent in Asia, but it can also be seen in South America.

Primary angiosarcoma of the spleen, a rare indication for splenectomy: a case report

INTRODUCTION AND IMPORTANCE

Primary angiosarcoma of the spleen is a rare condition with a nonspecific clinical presentation and is associated with a poor prognosis. We describe two patients with primary splenic angiosarcoma successfully treated with splenectomy and adjuvant chemotherapy.

CASE PRESENTATIONS

Case 1: A 50-year-old female presented with fatigue and left-sided rib, shoulder, and abdominal pain. A CT scan demonstrated a large splenic mass, and biopsy was diagnostic of angiosarcoma. An open en bloc resection of the spleen was performed, and pathologic examination confirmed high-grade angiosarcoma; the surgical margins were negative. The patient received pegylated liposomal doxorubicin (PLD) and ifosfamide; she demonstrated no evidence of recurrence with four years of follow-up. Case 2: A 70-year-old male presented with acute back pain. A CT scan demonstrated a splenic mass; biopsy was diagnostic of angiosarcoma. The patient underwent open splenectomy, and pathology revealed high-grade angiosarcoma; the surgical margins were positive. The patient received PLD and ifosfamide but presented three years later with metastatic tumor to the spine. The patient had a favorable tumor response to pembrolizumab. The patient's tumor burden remains stable at 5 years following splenectomy.

CLINICAL DISCUSSION

Angiosarcoma of the spleen is a rare clinical entity and is often challenging to diagnose early. Moratality is high, especially in the case of metastasis or spontaneous rupture.

CONCLUSION

Due to the rare nature of this tumor, optimal treatment is not known. Here, we show excellent response in two patients to surgery combined with adjuvant therapy.

Littoral cell angioma of the spleen: A case report

Spleen tumors are an uncommon disease. Littoral cell angioma belongs to the group of vascular tumors. It is believed that this tumor originates from the tissue of the red pulp sinuses, specifically from the cells that are lining the sinuses. If this rare tumor is diagnosed, it is necessary to search for synchronous or metachronous visceral neoplasia. Littoral cell angioma can also mimic metastatic lesion of the spleen. This case report wants to draw attention on this rare tumor of the spleen which is very often associated with other visceral malignancy.

Multi-Focal Splenic Tumour in a Belgian Patient and a Brief Review of the Literature on Littoral Cell Angioma

We describe the case of a 66-year-old woman with littoral cell angioma (LCA) confirmed by histopathology and immunohistochemistry, to our knowledge the first case in Belgium. LCA is an extremely rare primary vascular tumour of the splenic red pulp, probably originating from littoral cells. If a splenic mass and nodules are incidentally identified on imaging and the patient has no associated signs or symptoms, LCA should be suspected. Histopathology and adjacent techniques are mandatory for definitive diagnosis. Splenectomy followed by adequate follow-up is necessary to exclude underlying pathology.

LEARNING POINTS

Littoral cell tumour, although a very rare neoplasm, must be included in the differential diagnosis of splenic lesions observed by imaging.As imaging cannot differentiate between benign and malignant lesions, a definitive diagnosis is made only by histopathology and immunohistochemistry.Individuals diagnosed with littoral cell angioma must be carefully evaluated to exclude associated primary, secondary and synchronous malignancies as well as accompanying inflammatory/autoimmune disease.

Anatomy, immunohistochemistry, and numerical distribution of human splenic microvessels

The microvascular architecture of the spleen plays an important role in the immunological function of this organ. The different types of vessels are related to different reticular cells each with their own immunomodulatory functions. The present study describes an immunohistochemical and morphometric analysis of the various types of vessels in 21 human autopsy non-pathological splenic samples. On an area of 785,656.37 μm² for each sample, we classified and quantified the type and number of vascular structures, each according to their morphology and immunohistochemical profile, and obtained the ratios between them. The distribution of trabecular vessels and the characteristics of the venules are reviewed. In our material the so-called "cavernous perimarginal sinus" (anatomical structure previously described by Schmidt et al., 1988) was observed and interpreted as a curvilinear venule shaped by the follicle in contact with the trabecular vein. Our material comprised 261 trabeculae (containing 269 arterial sections and 508 venous sections), 30,621 CD34+ capillaries, 7739 CD271+ sheathed capillaries, 2588 CD169+ sheathed capillaries, and 31,124 CD8+ sinusoids. The total area (TA) (14,765,714.88 μm²) occupied by the sinusoidal sections of the 21 cases was much higher than the TA of the capillary sections (1,700,269.83 μm²). Similarly, the TA (651,985 μm²) occupied by the sections of the trabecular veins was much higher than the TA of the trabecular arteries (88,594 μm²). The total number of CD34+ capillaries and of sinusoids CD8+ was similar for the sum of the 21 cases, nevertheless there were large differences in each case. Statistically the hypothesis that the number of capillaries and sinusoids are present with the same frequency is discarded. In view of the absence of a numerical correlation between capillaries and sinusoids, we postulate that very possibly the arterial and the venous vascular trees are two anatomically independent structures separated by the splenic cords. We believe that this is the first work where splenic microvascularization is simultaneously approached from a morphometric and immunohistochemical point of view.

Laparoscopic splenectomy for littoral cell angioma of the spleen: A case report

RATIONALE

Littoral cell angioma (LCA) is a rare primary vascular neoplasm of the spleen. It can be benign or malignant. Pathology and immunohistochemistry are the gold standards for the diagnosis of LCA. Therefore, splenectomy is recommended for the purpose of diagnosis and treatment, and subsequent follow-up is necessary. There are limited reports about LCA. Here, we present a case of a female patient with LCA undergoing laparoscopic splenectomy in order to provide clinical experience in LCA treatment.

PATIENT CONCERNS

A 32-year-old female attended the outpatient Department of Hepatobiliary Surgery for follow-up of hepatic hemangiomas. The patient presented with intermittent abdominal distension, which was slightly under no obvious inducement.

DIAGNOSIS

Physical examination found no signs of abdominal tenderness and rebound tenderness, and liver and spleen were impalpable. The contrast-enhanced computed tomography (CT) showed multiple space-occupying lesions in the spleen, mottled low-density lesions, multiple hypoattenuating nodules with no contrast enhancement on the arterious phase. Delayed contrast-enhanced helical CT scan displayed incomplete filling of hypodense splenic lesions.

INTERVENTIONS

Given that it was uncertain whether it was a benign or a malignant tumor, a laparoscopic total splenectomy was performed.

OUTCOMES

The final pathological diagnosis was LCA. Her postsurgical course was uneventful, and no surgery-related complications were found. No signs of recurrence were observed in the 16 months after the operation.

LESSONS

LCA was a rare primary vascular neoplasm of the spleen, and laparoscopic splenectomy for LCA was safe and feasible, and postoperative course was uneventful. However, regular follow-up and long-time monitoring after splenectomy for LCA is recommended because of its potential malignant biological behavior.

The Sequence of the Evil: A Case Report of Idiopathic Noncirrhotic Portal Hypertension Associated With Littoral Cell Angioma of the Spleen, 4 Years After the Successful Treatment of a Colon Cancer

Idiopathic noncirrhotic portal hypertension is a rare clinical entity. Even rarer is the littoral cell angioma of the spleen. The almost simultaneous appearance of the two disorders in a 64-year-old Greek woman was a tempting stimulus for us to attempt to identify a common denominator between these two, apparently distinct, entities.

Langerin staining identifies most littoral cell angiomas but not most other splenic angiomatous lesions

Although littoral cell angiomas (LCAs) are phenotypically well characterized, the antibodies used to support the diagnosis identify many other cells in the normal spleen, and some may be found in other angiomatous lesions. Based on a langerin/CD207+ LCA index case, langerin and other selected immunohistochemical staining was performed on 10 LCAs, 20 other splenic angiomatous lesions, and 7 reactive lymph nodes to further investigate the role of langerin as a diagnostic tool. Ninety percent (9/10) of LCAs were langerin positive, whereas only 1 (5%) of 20 other splenic vascular lesions was partially positive (P < .00001). All LCAs were CD1a-, CD68+, CD34-, and CD8-; 20% were S100+, 70% CD21+, and 90% cyclin D1+. Ultrastructural studies of one LCA did not show Birbeck-type granules in definite lining cells. Sinus lining cells in 7 of 7 reactive lymph nodes showed partial langerin positivity, and 4 of 4 showed partial cyclin D1 positivity. In conclusion, langerin staining is an easily interpreted and highly sensitive and specific (sensitivity [0.90], specificity [0.95]) ancillary study to help distinguish LCA from other vascular tumors of the spleen. Whether this represents cross-reactivity or true CD207 expression is uncertain, as other immunohistochemical and ultrastructural studies do not support a Langerhans cell origin. The cyclin D1 staining seen in most LCA would be consistent with their expression of other selected vascular and histiocytic markers. The similar staining pattern in some lymph node sinus lining cells suggests a possible similar cell of origin, although LCA of lymph nodes is not described.

Littoral Cell Angioma: A Rare Cause of Pediatric Thrombocytopenia

Littoral cell angioma is a rare primary splenic vascular tumor, originating from the littoral cells lining the red pulp sinuses of the spleen, with variable presentation. Here, we present the case of a 2-year-old male child presenting with chronic thrombocytopenia which resolved after splenectomy.

Successful chemotherapeutic treatment for metastatic littoral cell angioma: A case report

RATIONALE

Metastatic littoral cell angioma (LCA) is extremely rare. No standard therapeutic strategy has been established, and the impact of chemotherapy has not yet been evaluated.

PATIENT CONCERNS

A 61-year-old woman was admitted because of bicytopenia. She had a splenectomy for LCA of the spleen 10 years earlier. Bone marrow aspiration was normal, and a computed tomography (CT) scan showed hepatomegaly with multiple liver tumors.

DIAGNOSES

Liver biopsy samples showed macrophage-like cell infiltration in the hepatic sinusoids. Metastatic LCA was diagnosed based on immunohistochemistry, imaging tests, and the clinical course.

INTERVENTIONS

Immunosuppressive agents, such as prednisolone and cyclosporine, were ineffective. Next, cytotoxic agents, such as etoposide, paclitaxel, and vincristine, were administered.

OUTCOMES

Cytotoxic agents showed a prominent effect against LCA. CT showed improvement of the hepatomegaly, and fluoro-deoxyglucose (FDG) uptake decreased markedly at a follow-up FDG- positron emission tomography (PET) scan.

LESSONS

Chemotherapeutic treatment based on hemophagocytic syndrome or angiosarcoma might have anti-tumor activity against metastatic LCA. Analysis of the molecular characteristics of this tumor is needed to develop better treatment options.

A Novel Presentation of Littoral Cell Angioma and Lymphatic Malformations in a Neonate

This case report describes a novel presentation of littoral cell angioma (LCA) and lymphatic malformations involving the omentum and mesentery. To our knowledge, these 2 entities have not been reported in the same patient. A 1-month term infant male presented with chylous ascites. During his workup, imaging detected splenic nodules. Biopsies revealed that the nodules were LCA and the chylous ascites was secondary to microscopic mesenteric and omental lymphatic malformations. Evaluation for a secondary malignancy, an underlying immunologic defect, and genetic causes were unrevealing. The presence of LCA and lymphatic malformations in the same patient suggests a genetic link between these 2 rare vascular disorders and may help elucidate the etiopathogenesis of these 2 poorly understood anomalies.

Optimum immunohistochemical procedures for analysis of macrophages in human and mouse formalin fixed paraffin-embedded tissue samples

Macrophages are closely related to various diseases and it is therefore important that the properties of macrophages are adequately evaluated in human diseases and mouse disease models. Immunohistochemistry (IHC) of formalin fixed paraffin-embedded (FFPE) samples is a very useful tool for examination of macrophages; however, an adequate IHC protocol is required for the examination of macrophage states. In this study, we assessed various antigen retrieval methods in order to devise the optimal protocols for staining of macrophages with a range of antibodies. Optimum combinations of primary antibodies and antigen retrieval protocols were determined; for example, heat treatment with ethylenediamine tetraacetic acid solution, pH 8.0, was the best procedure for IHC using mouse anti-Iba1 and human anti-CD11b, -CD163, -CD169, -CD204, and -CD206 antibodies. Moreover, we found that the immunoreactivity of sliced tissue sections decreased gradually over time in long term storage but that this immunoreactivity was preserved in storage at -80 °C in a deep freezer. The optimal IHC protocols and storage procedures that were determined in this study should be a useful tool for macrophage research.