Retiform hemangioendothelioma: an uncommon pediatric vascular neoplasm.

Retiform hemangioendothelioma is considered as a low grade angiosarcoma, commonly seen in 2(nd)-4(th) decade of life. The youngest patient reported is of 9 years of age. A 9-year-old boy was presented with an asymptomatic red patch on the chest since 1 year. There was an erythematous patch with nodule of about 5 mm near the distal margin. Biopsy from the nodule revealed numerous thin-walled branching vessels in dermis resembling rete testis, suggestive of retiform hemangioendothelioma. We, hereby, report this case for its rarity and uncommon clinical presentation in childhood period.

What was known?

Retiform hemangioendothelioma (RH) is a rare vascular neoplasm, which presents clinically as a slow growing asymptomatic solitary nodule or plaque either on extremities or trunk in 2nd-4th decade of life.

Introduction

Retiform hemangioendothelioma (RH) is a rare vascular neoplasm, which was first described in 1994 as a distinctive form of low grade angiosarcoma. It presents clinically as a slow growing asymptomatic solitary nodule or plaque either on extremities or trunk in 2nd-4th decade of life. Tumor has a slow indolent course with very high local recurrence and metastasizes very rarely. On histopathology, arborizing blood vessels are arranged in retiform pattern resembling the normal rete testis. Blood vessels are lined by monomorphic hobnail endothelial cells and infiltrated by lymphocytes. To date, only 32 cases have been reported worldwide.[1] We describe a case of 9-year-old boy presenting with solitary asymptomatic nodule of 1 year duration over the presternal area.

Case Report

A 9-year-old boy presented with asymptomatic reddish raised lesion over the chest since 1 year. Lesion started as a small red patch which gradually increased in size to present dimension. Over past few months, his mother noticed a small raised lesion in the centre of the patch. There was no history of trauma. There was no history of any discharge or bleeding. Examination revealed a well-defined, irregular erythematous patch of about 4 × 3 cm diameter over the presternal area. Towards the lower margin of the patch, there was a firm, non-tender, non-compressible nodule of about 5 mm diameter [Figure 1]. There was no bruit over the lesion.

Figure 1

Erythematous patch over presternal area with a nodule towards distal margin

Punch biopsy from the nodule revealed intradermal neoplasm composed of spindle cells arranged in sheets extending till subcutis [Figure 2]. Aggregates of the cells at foci were differentiating into vessels, which branched in a rete pattern reminiscent of rete testis [Figure 3]. Occasionally, endothelial cells were seen projecting into the lumen like a hobnail [Figure 4]. Few red blood cells were seen within the lumen. There was no atypia. The biopsied area grew back to slightly larger dimension than before.

Figure 2

Punch biopsy from the nodule reveals spindle cell neoplasm which extends into subcutis

Figure 3

Spindle cells are arranged in sheets as well as thin-walled branching vessels resembling rete testis

Figure 4

Closer view of a vessel reveals hobnail-like endothelial cells

Discussion

Retiform hemangioendothelioma is a rare vascular neoplasm of intermediate or borderline malignancy involving the skin and subcutaneous tissue. This entity was first described by Calonje et al. in 1994.[2] Although etiology is unknown, human herpes virus type 8, lymphedema, radiotherapy, non-cutaneous malignant neoplasms, and picibanil (OK-432) have been purported to be associated with RH.[34] RH commonly presents in young to middle aged persons (varies from 6-78 years) with female preponderance (male:female = 1:2).[3] They often present as solitary nodules or plaques of variable size (1-30 cm) over chest or extremities with an indolent course.[5] Although the local recurrence is very common, metastasis is infrequent with only three cases, which had lymph node metastasis and one death attributed to RH.[67]

Clinically, RH needs to be differentiated from cutaneous angiosarcoma, bacillary angiomatosis, Kaposi's sarcoma, dermatofibrosarcoma protuberans, and lymphoma. Histopathologically, RH reveals elongated, arborizing blood vessels lined by monomorphic bland endothelial cells with prominent apical nuclei and scanty cytoplasm resembling “match stick” or hobnail appearance. Perivascular and intravascular lymphocytic infiltrates are also present. Occasionally, intravascular papillae with hyaline cores can also be seen. In most tumors, there are solid areas composed of bland spindle cells or epitheloid cells which show vascular differentiation. Histopathologically, RH needs to be differentiated from Dabska's tumor, hobnail hemangioma, and angiosarcoma [Table 1].[8]

Table 1

Differential diagnoses of retiform hemangioendothelioma

Cutaneous angiosarcoma is more common in males and is associated with high risk of local recurrence, metastasis, and mortality. RH has high risk for local recurrence as in our case but low risk of metastasis with only once case of death reported till date. It is more common in females and affects wide spectrum of age group (9-78 years).

Immunohistochemically, the neoplastic cells react with CD31, CD34, factor VIII-related antigen, bound Ulex europeus agglutinin, and vimentin indicating vascular differentiation.[3] Rarely, they may express D2-40 and vascular endothelial growth factor receptor 3 (VEGFR-3), markers of lymphatic endothelium.[9] Tumor does not stain for keratins, epithelial membrane antigen, S-100 protein, and desmin. Moh's micrographic surgery is the treatment of choice.[10] Adjuvant radiotherapy is indicated in patients with large tumor size, local recurrence, and lymph node metastasis. Adjuvant chemotherapy with recombinant interferon alpha and low dose cisplatin have also been reported.[3]

What is new?

Lesions are typically nodules or plaques, but our patient had nodule within the plaque.