Kaposiform Hemangioendothelioma

Paclitaxel-based chemotherapy for aggressive kaposiform hemangioendothelioma of the temporomastoid region: Case report and review of the literature

BACKGROUND

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor of infancy and childhood. This tumor results in poor prognosis, and therefore, development of a more effective treatment is needed.

METHODS AND RESULTS

We describe an 11-year-old boy presenting with left facial palsy caused by aggressive KHE of the left temporomastoid region. He was treated with paclitaxel-based chemotherapy, because of the difficulty with complete surgical resection for anatomic factor, multiple lung metastases on diagnosis, and no response to conventional treatments. This treatment reduced the volume of primary tumor and lung metastatic lesions, but the efficacy was transitory.

CONCLUSIONS

Paclitaxel-based chemotherapy for aggressive KHE may be effective, therefore the multimodality therapy including paclitaxel of aggressive KHE, particularly in the head and neck, needs to be investigated in further studies.

Kaposiform hemangioendothelioma with Kasabach-Merritt phenomenon: successful treatment with embolization and vincristine in two newborns

Kaposiform hemangioendothelioma (KHE) is a rare vascular tumor and has a high mortality in newborns when associated with Kasabach-Merritt syndrome (KMS). In two newborns with KHE and severe KMS refractory to medical treatment, emergency embolization led to clinical improvement in the acute neonatal setting by reducing tumor volume, increasing the platelet count, and improving other clotting parameters. Systemic vincristine treatment was added for further tumor control. Both patients remained symptom-free at long-term follow-up.

Vascular and perivascular lesions of skin and soft tissues in children and adolescents

Vascular anomalies in children and adolescents are the most common soft tissue lesions and include reactive, malformative, and neoplastic tumefactions, with a full spectrum of benign, intermediate, and malignant neoplasms. These lesions are diagnostically challenging because of morphologic complexity and recent changes in classification systems, some of which are based on clinical features and others on pathologic findings. In recent decades, there have been significant advances in clinical diagnosis, development of new therapies, and a better understanding of the genetic aspects of vascular biology and syndromes that include unusual vascular proliferations. Most vascular lesions in children and adolescents are benign, although the intermediate locally aggressive and intermediate rarely metastasizing neoplasms are important to distinguish from benign and malignant mimics. Morphologic recognition of a vasoproliferative lesion is straightforward in most instances, and conventional morphology remains the cornerstone for a specific diagnosis. However, pathologic examination is enhanced by adjunctive techniques, especially immunohistochemistry to characterize the type of vessels involved. Multifocality may cause some uncertainty regarding the assignment of "benign" or "malignant." However, increased interest in vascular anomalies, clinical expertise, and imaging technology have contributed greatly to our understanding of these disorders to the extent that in most vascular malformations and in many tumors, a diagnosis is made clinically and biopsy is not required for diagnosis. The importance of close collaboration between the clinical team and the pathologist cannot be overemphasized. For some lesions, a diagnosis is not possible from evaluation of histopathology alone, and in a subset of these, a specific diagnosis may not be possible even after all assembled data have been reviewed. In such instances, a consensus diagnosis in conjunction with clinical colleagues guides therapy. The purpose of this review is to delineate the clinicopathologic features of vascular lesions in children and adolescents with an emphasis on their unique aspects, use of diagnostic adjuncts, and differential diagnosis.

Sirolimus for the treatment of complicated vascular anomalies in children

BACKGROUND

Vascular anomalies comprise a diverse group of diagnoses. While infantile hemangiomas are common, the majority of these conditions are quite rare and have not been widely studied. Some of these lesions, though benign, can impair vital structures, be deforming, or even become life-threatening. Vascular tumors such as kaposiform hemangioendotheliomas (KHE) and complicated vascular malformations have proven particularly difficult to treat.

PROCEDURE

Here we retrospectively evaluate a series of six patients with complicated, life-threatening vascular anomalies who were treated with the mTOR inhibitor sirolimus for compassionate use at two centers after failing multiple other therapies.

RESULTS

These patients showed significant improvement in clinical status with tolerable side effects.

CONCLUSIONS

Sirolimus appears to be effective and safe in patients with life-threatening vascular anomalies and represents an important tool in treating these diseases. These findings are currently being further evaluated in a Phase II safety and efficacy trial.

The successful management of diffuse lymphangiomatosis using sirolimus: a case report

Lymphangiomatosis is a rare and fatal congenital lymphatic malformation. Because the natural course of the disease affects multiple body systems, the management can be challenging. This article presents a novel approach to the treatment of diffuse lymphangiomatosis using sirolimus. The reported case involves a 4-month-old male with a known lymphatic malformation who presented to the emergency department with respiratory difficulties. Sirolimus was successful at significantly reducing our patient's mass at a relatively low target level of 5 to 10 μg/L. The use of sirolimus for the treatment of lymphangiomatosis should be studied further in the setting of a formal trial.

Kaposiform hemangioendothelioma in tonsil of a child associated with cervical lymphangioma: a rare case report

Kaposiform hemangioendothelioma (KHE) is an uncommon vascular tumor of intermediate malignant potential, usually occurs in the extremities and retroperitoneum of infants and is characterized by its association with lymphangiomatosis and Kasabach-Merritt phenomenenon (KMP) in certain cases. It has rarely been observed in the head and neck region and at times, can present without KMP. Herein, we present an extremely uncommon case of KHE occurring in tonsil of a child, associated with a neck swelling, but unassociated with KMP. A 2-year-old male child referred to us with history of sore throat, dyspnoea and right-sided neck swelling off and on, since birth, was clinicoradiologically diagnosed with recurrent tonsillitis, including right sided peritonsillar abscess, for which he underwent right-sided tonsillectomy, elsewhere. Histopathological sections from the excised tonsillar mass were reviewed and showed a tumor composed of irregular, infiltrating lobules of spindle cells arranged in kaposiform architecture with slit-like, crescentic vessels. The cells displayed focal lumen formation containing red blood cells (RBCs), along with platelet thrombi and eosinophilic hyaline bodies. In addition, there were discrete foci of several dilated lymphatic vessels containing lymph and lymphocytes. On immunohistochemistry (IHC), spindle cells were diffusely positive for CD34, focally for CD31 and smooth muscle actin (SMA), the latter marker was mostly expressed around the blood vessels. Immunostaining for HHV8 was negative and Ki-67 (proliferation marker) displayed focal positivity. Diagnosis of KHE was made. Platelet count was towards lower side of range. Postoperative imaging showed discrete, multiple fluid containing lesions in the right neck that were high on T2-weighed sequences, on magnetic resonance imaging (MRI) and ipsilateral intraoral mucosal growth. Fine needle aspiration cytology (FNAC) smears from neck swelling showed blood, fluid and lymphocytes. Possibility of a coexisting lymphangioma was considered. The patient was offered sclerotherapy and is on follow-up. This case forms the second documented case of KHE at this site, along with its unique association with neck lymphangioma. KHE has distinct histopathological features and can be sorted out from its other differentials like juvenile hemangioma and Kaposi's sarcoma. IHC stains are useful in substantiating a definite diagnosis.

Epithelioid hemangioendothelioma of the middle ear in a child

The differential diagnosis of middle ear masses encompasses a wide variety of pathologic conditions. In this report, we describe the case of a 6-year-old girl who presented with facial nerve weakness and was found to have a middle ear mass. The mass was excised, and final pathology revealed hemangioendothelioma. This report describes the youngest patient with this diagnosis presenting as a middle ear mass in the Western literature. This article provides this patient's presentation, imaging and histopathologic findings, and clinical course and reviews the current literature on this unique pathologic diagnosis.

Management of hemangiomas and other vascular tumors

Vascular tumors of childhood are typically benign. The 4 most common types are infantile hemangioma (IH), congenital hemangioma (CH), kaposiform hemangioendothelioma (KHE), and pyogenic granuloma (PG). Vascular tumors must be differentiated from vascular malformations. Although tumors and malformations may appear as raised, blue, red, or purple lesions, their management differs significantly.

Kaposiform hemangioendothelioma with adolescent thoracic scoliosis: a case report and review of literature

Kaposiform hemangioendothelioma (KHE) is a rare locally aggressive vascular tumor that usually presents as a superficial or deep soft tissue mass with associated cutaneous lesions. We report a unique spinal KHE with painless thoracic scoliosis in a 14-year-old girl. She underwent simultaneous tumor biopsy, spinal deformity correction and fusion. At 3 years follow-up, the patient's MRI showed no significant deterioration of process without any therapy. KHE presenting as scoliosis is rare and to our knowledge this is the first recognized case in the reported world literature.

How airway venous malformations differ from airway infantile hemangiomas

OBJECTIVE

To compare airway infantile hemangiomas (IHs) and venous malformations (VMs) clinically, radiographically, endoscopically, and histologically.

DESIGN

Retrospective cohort study.

SETTING

Tertiary care pediatric hospital.

PATIENTS

The study included patients seen in the Vascular Anomaly Clinic, Seattle Children's Hospital, Seattle, Washington, between 2001 and 2008.

METHODS

All patients with airway vascular anomalies were identified by searching the Vascular Anomaly Quality Improvement Database and hospital discharge data. The data, which were analyzed with descriptive statistics and the Fisher exact test, included presenting age, sex, presenting signs, lesion site, and radiographic, endoscopic, and histologic findings..

RESULTS

Seventeen patients with airway lesions were identified, 6 with VMs and 11 with IHs. Patients with VMs presented at a mean (SD) age of 11.3 (13.7) months (age range, 3-39 months), while those with IHs presented at 3 (1.8) months of age (age range, 1-6 months) (P = .03). The patients with IHs were predominantly female (9 of 11 [81%]), while no sex difference was noted among the patients with VMs (3 of 6 [50%]). All patients with IHs presented with stridor and cutaneous lesions, whereas patients with VMs more often presented with hemoptysis or dysphagia (P = .001). Computed tomographic angiograms demonstrated enhancing endolaryngeal lesions in all IHs, while VMs enhanced poorly. Endoscopically, IHs were transglottic, while VMs were postcricoid or epiglottic (P < .001). Histologically, immunostained lesions showed submucosal lobules of capillaries lined by GLUT-1 (glucose transporter isoform 1)-positive endothelium in IHs, whereas VMs consisted of loosely organized venous channels that lacked GLUT-1 staining.

CONCLUSION

Patients with airway IHs and VMs differ in presenting age and signs, sex, airway lesion location, enhancement on computed tomographic angiograms, and histologic appearance.

Treatment of childhood kaposiform hemangioendothelioma with sirolimus

Sirolimus (Rapamune), a mammalian target of Rapamycin (mTOR) inhibitor, which has been used extensively in children following solid organ transplantation, has been demonstrated to have anti-angiogenic activity in pre-clinical models. Limited experience suggests that it may have application to the treatment of vascular lesions. We describe our experience with a 1-year-old female with a kaposiform hemangioendothelioma and Kasabach-Merritt phenomenon who had rapid and dramatic response to sirolimus (0.1 mg/kg/day). This case provides further rationale for clinical trials of sirolimus in the treatment of vascular lesions.

Pediatric Vascular Tumors and Malformations

Pediatric vascular tumors and malformations, comprising a broad category of lesions often referred to as vascular anomalies, are a heterogenous group of clinicopathologically distinct entities. Pathologists, clinicians, and radiologists have traditionally lumped these lesions under the generic term, hemangioma, sometimes qualified by modifiers, such as capillary or cavernous. Advances in understanding underlying pathogenetic mechanisms support more specific classification and more specifically targeted therapies. Multidisciplinary consensus has moved toward a biologically based classification system and therapeutic approach for dealing with these lesions. This content focuses on the histologic, immunophenotypical, and clinical features that distinguish the major types of vascular tumors and malformations presenting in infancy and childhood. Pathogenic mechanisms are also briefly reviewed.

Kaposiform hemangioendothelioma arising in the deltoid muscle without the Kasabach-Merritt phenomenon

Kaposiform hemangioendothelioma (KHE) is a rare tumor that occurs nearly exclusively during infancy and childhood. It has features common to both capillary hemangioma and Kaposi sarcoma and for that reason many terms have been used for these tumors including "Kaposi-like infantile hemangioendothelioma" and "hemangioma with Kaposi sarcoma-like features." KHE typically presents as an ill-defined, red to purple, indurated plaque and is often complicated by the Kasabach-Merritt phenomenon (KMP), a condition of severe thrombocytopenia and consumptive coagulopathy. Knowledge of the radiological findings of this uncommon tumor might be helpful for diagnosis. We present the MRI features of a case of KHE with neither typical skin lesions nor the Kasabach-Merritt phenomenon.

Kasabach-Merritt phenomenon

The objective of this article is to provide a comprehensive overview of the Kasabach-Merritt Phenomenon. The clinical presentation, laboratory findings, vascular pathology, and pathophysiology are discussed.

Kaposiform hemangioendothelioma of the choledochus

Kaposiform hemangioendothelioma (KHE) is a rare, locally aggressive vascular neoplasm that mainly occurs during childhood. Although KHE may involve various organs, involvement of the choledochus has not been reported. We report a case of KHE in a 5-month-old male infant. The patient was admitted with icterus and acholic stool. Contrast computed tomography revealed a vascular tumor in the hepatic portal region causing biliary obstruction. Excision of the extrahepatic duct and hepatoportoenterostomy were performed successfully, and he has been well during 3 years of postoperative follow-up.

Successful treatment of kaposiform hemangioendothelioma and tufted angioma with vincristine

BACKGROUND

Kaposiform hemangioendothelioma (KHE) and tufted angioma (TA) are rare, locally aggressive vascular tumors. Although currently classified as separate entities, they are becoming increasingly recognized as a spectrum of the same pathology. There is a well-recognized association with Kasabach-Merritt phenomenon KHE and TA are considered neoplasms of intermediate malignancy because of infiltrative growth, local aggressiveness, and variable prognosis. To date, definitive treatment for these vascular tumors has had limited success.

AIM

To evaluate the safety, efficacy, and role of vincristine in the treatment of KHE and TA.

METHODS

Case review of patient files and pathology reports at The Children's Hospital at Westmead from 1995 to 2009.

RESULTS

Twelve cases with KHE or TA were identified. Seven cases were treated with vincristine. The survival rate in the vincristine group was 100%. Mean age of diagnosis was 30 months (range birth to 9 y). 6 patients were female (85.7%). Mean time of the follow-up was 4 years (range 4 mo to 8 y). Out of the 7 cases treated with vincristine, 3 patients had associated Kasabach-Merritt phenomenon (43%). Complete resolution, regression in size, and improvement in analgesia were found in 1 case (14%), 3 cases (43%) and 2 cases (29%), respectively. Vincristine related side effects occurred in 2 cases (29%).

CONCLUSIONS

Vincristine is an effective treatment option for KHE/TA. It is associated with a low side effect profile and should be considered as the first-line agent.

Unique histologic variants of cutaneous Kaposi sarcoma

BACKGROUND

Kaposi sarcoma (KS) is a low-grade angioproliferative neoplasm derived from lymphatic endothelium. Lesions progress from early patch stage into plaques that ultimately form tumor nodules. Several histological variants of KS have been described. The aim of this study is to describe 5 new histopathologic variants of cutaneous KS.

METHOD

Skin biopsy material submitted to a South African dermatopathology practice diagnostic of KS was reviewed. Formalin-fixed, paraffin-embedded tissue was routinely processed and stained with hematoxylin and eosin. Confirmatory immunohistochemical stains included CD31 and latent nuclear antigen-1 (human herpesvirus 8).

RESULTS

All biopsies were procured from HIV-positive patients with a clinical diagnosis of cutaneous KS tumor. Five distinct histologic KS variants, not previously well characterized in the literature, were identified including glomeruloid KS, telangiectatic KS, ecchymotic KS, KS with myoid nodules, and pigmented KS. Tumor cells in all of these variants were immunoreactive for CD31 and latent nuclear antigen-1.

CONCLUSIONS

These unique cases highlight the ability of KS to exhibit variable histomorphology. Their clinical significance requires further study. Dermatopathologists should be aware of these newly described variants to avoid the potential for their misdiagnosis.

Kaposiform hemangioendothelioma of the kidney: an unusual presentation of a rare vascular neoplasm

Kaposiform hemangioendothelioma (KHE) is a rare, locally aggressive, vascular spindle-cell proliferation, with resemblance to Kaposi sarcoma. Usually, this tumor occurs in the skin and the retroperitoneum. We described a girl with a kidney localization and extension into the inferior vena cava and even into the right atrium. The case presented here is unique in 2 ways. First, kidney involvement of KHE has never been described in the literature until now. Second, and most remarkably, extensive tumor thrombosis suggests surgical excision even with cardiopulmonary bypass. The KHE of the kidney is a rare tumor but should be taken into account in the differential diagnosis with other pediatric renal neoplasms.

Kaposiform (spindle cell) hemangioendotelioma in a child with an unusual presentation

We describe a male child with multifocal kaposiform hemangioendothelioma in the right and left cervical region with development of Kasabach-Merritt syndrome. Treatment with interferon-alpha resulted in a good but only temporary clinical response.He relapsed 3 times with regrowth of the right cervical tumor. Involvement of the liver is suspected, because normalization of the liver size followed after the treatment with interferon-alpha. The question remains whether the multiple osteolytic bone lesions also reflect kaposiform hemangioendothelioma localization.

[Retiform haemangioendothelioma: a case report]

Retiform haemangioendothelioma is a locally aggressive, very rarely metastasizing vascular lesion. Histologically, it is characterized by distinctive arborizing blood vessels resembling "rete testis" and lined by endothelial cells with characteristic hobnail morphology. We present an additional case, in the leg of a 64-year-old patient. We discuss the classification of hemangioendotheliomas. The term hemangioendothelioma should be restricted to vascular tumours of "intermediate malignancy" but has been used to designate tumours with variable histological features and clinical behaviour. Spindle cell hemangio(endothelio)ma is currently regarded as a benign reactive lesion. Kaposiform hemangioendothelioma is potentially lethal due to consumption coagulopathy but no metastasizing case has been reported. Epithelioid hemangioendothelioma is associated with a significant metastatic risk and has been included in the category of malignant vascular tumors. The vascular lesions fulfilling the strict definition of hemangioendothelioma include retiform hemangioendothelioma, papillary intralymphatic angioendothelioma "Dabska's tumor", composite hemangioendothelioma and perhaps the controversial polymorphic hemangioendothelioma.

Kaposiform hemangioendothelioma (with Kasabach Merritt syndrome) of the head and neck: case report and review of the literature

An infant initially diagnosed with a parotid hemangioma presented with stridor and thrombocytopenia. Diagnosis of Kaposiform hemangioendothelioma was confirmed with biopsy. The child succumbed to multi-system organ failure related to consumptive coagulopathy despite aggressive medical management. Kaposiform hemangioendothelioma is a rare head and neck tumor that may be mistaken for a hemangioma on preliminary diagnosis, which may lead to increased morbidity and mortality especially in the setting of Kasabach-Merritt phenomenon. A platelet count may provide an early and important clue to the possibility of coagulopathy; prompting physicians to look for a diagnosis other than a simple hemangioma.

Kaposiform hemangioendothelioma in multiple spinal levels without skin changes

Kaposiform hemangioendothelioma is a rare vascular tumor of childhood that is locally aggressive but has little metastatic potential and by itself is not known to be lethal. It most commonly presents as a superficial or deep soft tissue mass with associated cutaneous lesions. Kasabach-Merritt phenomenon, a condition characterized by profound thrombocytopenia and life-threatening hemorrhage, often is associated with kaposiform hemangioendothelioma. Six cases of kaposiform hemangioendothelioma have been reported in bone, two of which were located in extracraniofacial bones. We report a diagnostically challenging case of a 6-year-old girl with kaposiform hemangioendothelioma of the thoracolumbar spine without Kasabach-Merritt phenomenon or cutaneous lesions.

Pediatric soft-tissue tumors and pseudo-tumors: MR imaging features with pathologic correlation: part 1. Imaging approach, pseudotumors, vascular lesions, and adipocytic tumors

A wide spectrum of entities may give rise to soft-tissue masses in children, including benign and malignant tumors, pseudotumors, and both neoplastic and nonneoplastic vascular lesions. Because of its excellent tissue contrast, multiplanar capability, and lack of ionizing radiation, magnetic resonance (MR) imaging has become the modality of choice in the evaluation of deep and large soft-tissue masses in children. In the vast majority of cases, however, accurate interpretation of the MR imaging findings requires correlation with the clinical findings. For example, in most posttraumatic and inflammatory pseudotumors, the clinical history is fundamental to establishing the diagnosis. In the evaluation of periarticular cysts, the location of the mass and its relationship to a joint are crucial for diagnosis, whereas in the evaluation of vascular lesions, including hemangiomas and vascular malformations, clinical findings combined with MR imaging findings are needed for accurate diagnosis in most cases. The identification of fat within adipocytic tumors is useful, but tissue biopsy may be required for final diagnosis. Nevertheless, MR imaging is useful in determining the origin and character of pediatric soft-tissue masses, defining their extent and their relationship to adjacent structures, and performing posttherapy follow-up.

[Soft tissue tumors in neonates]

Soft tissue tumors account for approximately 25% of neonatal tumors and are most often benign (more than 2/3 of cases). Vascular tumors are the most frequent benign tumors and infantile hemangioma accounts for 32% of these tumors, affecting 1 out of 200 children at birth. Kaposiform hemangioendothelioma (KH) is a rare vascular tumor with locally aggressive behavior. More than 50% of KH are associated with the Kasabach-Merritt phenomenon, a condition characterized by thrombocytopenia and consumptive coagulopathy. Malignant soft tissue tumors are, after neuroblastoma, the second cause of cancer in neonates. Infantile fibrosarcoma (IF) is a rare tumor that most often affects the extremities of children aged 4 years or younger. A recurrent t(12;15) (p13;q25) rearrangement fusing the ETV6 gene with the NTRK3 neurotrophin-3 receptor gene has been identified in IF. Complete conservative surgical resection is usually curative. Chemotherapy is indicated when initial surgical removal cannot be accomplished without unacceptable morbidity. Prognosis of IF is excellent, with reported overall survival rates ranging from 80 to 100%. Neonatal rhabdomyosarcoma (RMS) is a rare tumor (0.5-1% of RMS). The primary tumor predominantly involves the limbs and the genitourinary tract. Treatment is based on age-adapted chemotherapy and surgery. Prognosis of RMS in children less than 1 year old appears to be comparable with that of older children.

Laryngeal kaposiform hemangioendothelioma: case report and literature review

The kaposiform hemangioendothelioma (KHE) is an uncommon vascular neoplasm of borderline or intermediate malignant potential in which involvement of the head and neck region is rare. A 5-year-old girl was admitted to the emergency room with abrupt massive hemoptysis. Transoral laryngoscopy revealed a round, reddish mass with active bleeding on the anterior portion of the left vocal fold region. Since re-hemoptysis and large amount of aspiration caused breathing difficulties for the patient, suspension exam was performed under general anesthesia. Mass excision and thorough bleeding control was performed with laser assisted laryngo-micro system. Postoperatively, there was no further bleeding. The pathologic diagnosis of the tumor was KHE. To the best of our knowledge, this is the first report of a KHE in the larynx presenting as recurrent hemoptysis in childhood.

Mediastinal and neck kaposiform hemangioendothelioma: report of three cases

Kaposiform hemangioendothelioma is an aggressive vascular tumor, named for its striking histologic resemblance to Kaposi sarcoma and locally invasive growth. Mortality is high, and ranges from 10% to 24% for all kaposiform hemangioendothelioma lesions, with a significantly higher mortality for deep soft-tissue or visceral lesions occurring in infants less than 6 months. Mediastinal and neck kaposiform hemangioendothelioma in particular merit special discussion, as involvement of these critical anatomic locations results in significant site-specific therapeutic challenges due to invasion of vital structures, inherent delays in establishing histopathologic confirmation, and difficulties in monitoring disease status. We report our experience with three cases of mediastinal and neck kaposiform hemangioendothelioma, emphasizing the unique diagnostic and management challenges, variable response to treatment and outcome of this anatomic variant of kaposiform hemangioendothelioma.

Vincristine and Corticosteroids as First-Line Treatment of Kasabach-Merritt Syndrome in Kaposiform Hemangioendothelioma

Background:

Historically, patients with the consumptive coagulopathy Kasabach-Merritt syndrome (KMS) have been treated with systemic corticosteroids as first-line therapy, but many patients do not respond. Recently, there have been increasing reports of the use of the chemotherapeutic drug vincristine in these patients.

Objective:

To report a case of a newborn with a kaposiform hemangioendothelioma (KHE) of the right leg associated with KMS treated successfully with vincristine and oral corticosteroids.

Methods:

The patient's chart and the literature on the subject were reviewed using Medline and PubMed.

Results:

Treatment with vincristine and corticosteroids lead to sustained shrinking of the tumor and correction of the thrombocytopenia and coagulopathy through 1 year of age. We believe this is the first report in the North American literature of corticosteroids and vincristine being used concomitantly as first-line therapy for KHE with KMS.

Conclusion:

Vincristine and corticosteroids should be considered first-line treatment for KMS.

CD34-reactive tumors of the skin. An updated review of an ever-growing list of lesions

Over the past few years, a growing number of cutaneous tumors expressing CD34 is being reported. The list contains benign and malignant neoplasms as well as reactive and hamartomatous lesions of diverse lineages of differentiation, including fibroblastic, myofibroblastic, fibrohistiocytic, vascular, neural, adipocytic, smooth muscle, hematopoietic, melanocytic and epithelial. The more frequent diagnostic difficulties are found in spindle cell proliferations, mainly in those of the fibrocytic lineage. In part, this is because of the fact that in this area are, aside to well-defined entities, histologically and clinically diverse, recently reported cutaneous CD34-reactive lesions, whose definitions, limits and relationships are not completely established. The CD34 expression plays a key role in the differential diagnosis of some tumors, such as dermatofibrosarcoma protuberans, epithelioid sarcoma or pleomorphic hyalinizing angiectatic tumor of soft parts, with important therapeutic consequences. In others, as in desmoplastic trichilemmoma, it can help to resolve diagnostic problems in concrete cases. Finally, in many of the CD34-positive lesions, the diagnosis with the hematoxylin and eosin stain is straightforward. However, in all of them, the knowledge of the immunohistochemical profile contributes to our understanding of the cutaneous pathology.

Kaposiform hemangioendothelioma

Kaposiform hemangioendothelioma (KHE) is a rare, locally aggressive vascular neoplasm that mainly occurs during childhood. It generally originates on the skin, usually affecting deeper tissue by infiltrative growth. It appears as one or multiple masses, and in most cases is associated to consumptive coagulopathy (Kasabach-Merritt syndrome), and lymphangiomatosis. Although visceral involvement is very uncommon, several cases with bone, retroperitoneal, or mediastinal involvement have been described. These tumors tend to be locally invasive, but are not known to produce distant metastases. The development of KHE in adolescents or in adults is very rare, but cases have also been described. Several factors are associated with the outcome of patients with KHE: accessibility to surgical excision, location (cutaneous versus visceral), size of tumoral mass, clinical response to interferon and glucocorticoids, and the absence of lymphangiomatosis and Kasabach-Merritt syndrome, may result in partial remissions. On the other hand, bulk visceral masses lead to a 40-50% mortality rate, mainly due to progressive failure of the infiltrated organ(s), in spite of interferon, glucocorticoids, and combined chemotherapy. In conclusion, the onset of a consumptive coagulopathy following the presence of a vascular tumor, in children as well as in older patients, should spark suspicion of KHE, among other entities.