Projects

1. Case report

A 4-year-old boy presented with swelling of the left great toe and a non-healing ulcer at the tip with mild pain while walking. There was no antecedent history of trauma or pricks. 8 months back parents of the boy had noticed a gradually increasing small swelling at the tip of the great toe with hyperpigmentation. After a course of antibiotics by the primary Physician, the unresponsive swelling was biopsied leaving behind an ulcer that failed to regress. The biopsy was reported as vascular lesion suggestive of Dabska tumor following which the boy was referred to us.

On examination there was a diffuse swelling on the ventral aspect of left great toe with bluish discolouration of overlying skin extending till the inter-phalangeal joint. An ulcer of size 1.2 × 1.5 × 1.2 cm was present at the tip with irregular margins, sloughed out floor and no discharge. It was fixed but the underlying bone was not distorted (Fig. 1). Peripheral pulses were well felt and there was no inguinal or iliac lymphadenopathy. No similar lesions existed elsewhere in the body. After ensuring no local bony erosion on X-ray, confirming the report of Dabska tumor with the previous biopsy slide review and a normal Chest X-ray, the boy was subject to left great toe dis-articulation accounting to wide local excision after a written informed consent.

Histopathology (Fig. 2) revealed lesion in dermis composed of dilated anastomosing vascular channels some with intra luminal papillary formations and tufting. The tufts were lined by plump cuboidal endothelial cells with mild pleomorphism, round vesicular nuclei, scant to moderate cytoplasm. The papillary cores were hyalinised with eosinophilic basement membrane like material and mild lymphocytic infiltrate. There was no involvement of the underlying bone. The findings were consistent with Dabska tumor. 2. Discussion

Endovascular Papillary Angioendothelioma is synonymous with Dabska tumor, a tribute to Maria Dabska who first described it in 1969 as a tumor primarily involving skin and subcutaneous tissues in children. It was also called “malignant endovascular papillary angioendothelioma” as three of the six affected children had regional lymph node metastases and one among them died of pulmonary metastasis [1].

Fanberg et al. studied 12 cases and renamed these tumors as “Papillary Intra-lymphatic Angio-endothelioma (PILA)” due to the presence of lymphatic vessels in histology thereby distinguishing them from a closely related Retiform hemangio-endothelioma. Most recently WHO tumor classification specified these tumors as “rarely metastasizing lymphatic vascular neoplasms” [2].

Since its discovery, only 40 cases have been reported, Among the initial 30 cases (18 in children and 12 in adults) no sex predilection is noted. The oldest patient is a 83yr old female with a neck swelling [3]. A few unusual sites of occurrence are in the oral cavity, tongue, bone (femur/clavicle), spleen and testis [[4], [5], [6], [7]] with a sporadic case report of Dabska tumor in the dural sac of an occipital encephalocele [8]. Our Case describes the first occurrence of this entity in toe without bone involvement as an ulcer.

The lesion comprises of cuboidal endothelial cells lining the vascular structures and characterized by a high nuclear cytoplasmic ratio with atypically placed nucleus that produces a surface bulge, giving the appearance of “hobnail” or “matchstick” [9] with peri and intravascular lymphocytic infiltrates. The cells stain positive for Von-Willebrand factor, CD31, CD34 and vascular endothelial growth factor receptor-3 (VEGFR-3) podoplanin (D2-40) [10]. In our case the histology was classical as is described above, highlighted in Fig. 2 and hence immuno-staining was deferred. Other neoplasms exhibiting similar characteristics are retiform hemangioendothelioma, angiosarcoma, reactive angioendotheliomatosis and benign intravascular endothelial hyperplasia. But these can be differentiated by subtle specific differences in architectural features, the extent of cytological atypia and immunostaining differences observed between the above-mentioned markers, only the Dabska's tumor being positive for podoplanin (D2-40).

Dabska tumors have excellent prognosis after complete, wide excision with only one patient reported to have died of pulmonary metastasis [11]. However long-term follow-up is required to assess locoregional recurrence and metastasis. Because of the rarity of this tumor, there is no universal consensus in the follow-up protocol. Our patient is well with no symptoms and a healed wound at a year's follow up.