Tufted angioma is a rare, slowly progressive benign vascular tumor which can have variable clinical morphology. It can present as red or bluish to violaceous papule, plaque or nodule over neck, upper back and proximal part of limbs typically in childhood and infancy. These lesions may also develop in adults or the elderly [
7]. There is no sex predilection [
8]. The lesions range from few millimeters to few centimeters in size but may be extensive covering larger areas and can be multifocal [
9]. Most of the lesions are asymptomatic but may present with tenderness, hypertrichosis and hyperhidrosis [
8,
10,
11]. Tenderness, hypertrichosis, and induration can be useful in differentiating TA from common hemangioma [
12]. Microscopically TA has a classical morphology. It is found dispersed in the dermis and occasionally extends into the subcutaneous tissue and is seen as discrete round to ovoid angiomatous aggregates [
8]. These aggregates are composed of relatively bloodless, poorly canalized capillaries. Capillaries are lined by plump endothelial cells, which may show slight spindling. The endothelial cells show reactivity for several markers, including CD31, CD34 and von Willebrand factor (factor VIII). In our case, CD34 was used to highlight the endothelial cells. Pericytes are seen surrounding the capillaries and are the predominant cellular component of TA. These cells have indistinct cell boundaries, scant cytoplasm, and oval to slightly elongated nuclei with bland morphology. Dilated crescent shaped lymphatic like vascular channels are seen surrounding the angiomatous lobules. These channels are lined by plump to flattened cells with oval to slightly spindly nuclei.
Tufted angioma in childhood needs differentiation from strawberry nevi and kaposiform hemangioendothelioma [
4]. Angiomatous aggregates of strawberry nevi are more massive and replace wider planes. Eyelid lesions tend to have involvement of deeper orbital structures. Kaposiform hemangioendothelioma is morphologically intermediate between strawberry nevi and Kaposi sarcoma [
8], is more commonly seen in childhood and shows capillaries with lobular pattern that are locally infiltrative. Periphery of the tumor shows micro thrombi within the capillaries. Angioblastoma of Nagakawa (TA) should not be confused with the term giant cell Angioblastoma (GCA), which is a rare hemangioma-like lesion of infancy [
13]. GCA is characterized by nodular, linear and plexiform granuloma–like aggregates of histiocytes–like cells and giant cells, surrounding capillary sized vessels lined by plump endothelial cells. Background is loose, mesenchymal with mononuclear inflammatory cell infiltrate and mast cells [
13,
14]. In adults, TA needs to be differentiated from Kaposi’s sarcoma and low grade angiosarcoma [
2,
7]. Endothelial cells in TA appear plump to slightly spindled and lack the spindling of Kaposi’s sarcoma [
8]. Vascular spaces of TA are relatively bloodless when compared to blood filled spaces in Kaposi’s sarcoma. Lack of nuclear atypia excludes angiosarcoma [
7]. Other diagnostic hints of angiosarcoma include presence of sinusoid like spaces, dissection of collagen, mitoses, necrosis and haemorrhage [
8,
15]. Cases with clinical suspicion of TA should be worked up with complete physical examination and complete blood count with red cell morphology to exclude consumptive coagulopathy and Kasabach–Merritt syndrome (KMS) [
16,
17]. Prothrombin time and activated tpartial thromboplastin time should be performed in patients with thrombocytopenia. Rare association of Port wine stain with TA is also reported [
5,
17]. Spontaneous regression is known, but is exceptionally rare and regression may occur over a period varying from months to years [
18,
19].