Case 5-1 -

Dabska's Tumor (Papillary Intralymphatic Angioendothelioma PILA) Dr. Eduoardo Calonje

Clinical history: Female, 35. Recurrent tumour on abdomen. First excision performed in 1999. Case 5-1 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Histological features -Dermal and focally subcutaneous tumor -Small, medium and large, thin-walled vascular spaces with lymphatic-like appearance -Some spaces contain proteinaceous pink material in their lumina -Vascular channels are lined by a single layer of slightly hyperchromatic hobnail endothelial cells with no cytological atypia -A striking feature is the formation of intraluminal papillary projections with collagenous cores lined by hobnail endothelial cells (flower-like) -No mitotic figures are seen -In the surrounding dermis there is a focal mild to moderate mononuclear inflammatory cell infiltrate composed of lymphocytes Diagnosis: Dabska's tumor (Papillary intralymphatic angioendothelioma PILA) Dabska's Tumor (Papillary intralymphatic angioendothelioma) Papillary intralymphatic angioendothelioma (PILA) is a very rare tumor that was first described in by Dabska in 1969 as malignant endolymphatic angioendothelioma. Since then, only very few additonal cases had been reported in the literature, and there is lack of consensus regarding its specific histologic features. Recently, a series of cases was published and the alternative name of papillary intralymphatic angioendothelioma (PILA) has been suggested. Although tumors present mainly in infants and children around 25% of patients are adults. There is no sex predilection and the preferred sites of presentation are the limbs. Clinical features are not distinctive and lesions present as a slowly growing nodule or plaque. Classification as a tumor with low-grade malignant potential is based on reports of local recurrence and rare regional lymph node metastasis in the original series. However, follow-up in 8 of the 12 cases recently reported, showed no evidence of either local recurrence or distant spread. It is therefore likely that this tumor is benign but confirmation of these findings is required in larger series with longer follow-up. Histology shows a dermal and often subcutaneous tumor composed of markedly dilated, thin-walled vascular channels resembling a cavernous lymphangioma. The vascular channels are lined by bland endothelial cells with a hobnail appearance and no mitotic activity. These cells have protruding nuclei and very scanty cytoplasm resulting in a typical hobnail appearance. A prominent intra- and extravascular lymphocytic inflammatory cell infiltrate is often present, and intravascular papillae with collagenous cores are a typical finding. The lymphocytes are closely apposed to the hobnail endothelial cells. Differential Diagnosis Retiform hemangioendothelioma Retiform hemangioendothelioma is a distinctive variant of low-grade angiosarcoma. Age range is wide but it is more common in young adults with the same sex incidence. It presents as a slowly growing asymptomatic mass with predilection for the distal extremities, especially the lower leg. Association with radiation therapy or chronic lymphoedema rarely occurs. Multiple lesions have been documented once. Local, often repeated, recurrences are common, but so far only one case has metastasized to regional lymph nodes and a further case has metastasize to soft tissues close to the primary tumor. No distant spread or tumor-related death has been reported. Tumors are infiltrative and involve the dermis and subcutaneous tissue. The name of the neoplasm derives from the striking scanning magnification resemblance to the rete-testis. Long, thin-walled arborising vascular channels lined by a single layer of monomorphic endothelial with no atypia, apical nuclei and scanty cytoplasm (hobnail endothelial cells) are seen. The cytoplasm of tumor cells is indistinct and seems to blend with the surrounding collagen. The nuclei protrude into the vascular lumina resulting in a characteristic hobnail appearance. Intravascular papillae lined by hobnail endothelial cell and with a collagenous core may be present. Numerous small round T lymphocytes are often but not always seen both in the surrounding stroma and within the vascular lumina. Frequently, these lymphocytes seem to be very closely opposed to the hobnail endothelial cells. In some tumors there is a solid component consisting of bland spindle-shaped cells and rarely, focal epithelioid endothelial cells are seen. Retiform hemangioendothelioma shows some overlap with papillary intralymphatic angioendothelioma (PILA, Dabska's tumor) and it has been proposed that the former is an adult variant of the latter. However, in PILA, lacks a retiform growth pattern, and it is characterized by cavernous lymphangioma-like vascular spaces with prominent intravascular papillae containing collagenous cores. Targetoid hemosiderotic hemangioma (hobnail hemangioma) is always more superficial, has a wedge-shaped architecture, lacks an infiltrative margin and hobnail endothelial cells are only focally present mainly in superficial vascular channels. Conventional angiosarcoma usually presents in a different clinical setting and is characterized histologically by at least focal pleomorphism, multilayering and mitoses. It is worth mentioning however, that exceptionally, conventional angiosarcoma may show areas of retiform hemangioendothelioma and the diagnosis should emphasize the component with the highest histological grade as this is likely to determine prognosis. Composite Hemangioendothelioma Composite hemangioendothelioma is a recently described low-grade malignant vascular tumor with a tendency for local recurrence but very low metastatic potential. It is defined as a neoplasm containing a mixture of histologic patterns including benign, intermediate and/or malignant. It is a very rare tumor presenting mainly in adults with equal sex incidence. Most tumors occur in the extremities with predilection for the hands and feet and present as a long-standing red/blue nodule or plaque. Lymphedema is a frequent association. Local recurrence occurs in about 50%. Only a single case has been reported to metastasize to a regional lymph node and to the soft tissues of the thigh. The prognosis is likely to depend on the component with the highest histologic grade but this should be estimated in larger series of cases with adequate follow-up. The tumor is poorly circumscribed and infiltrative involving the dermal and subcutis. The different components vary from lesion to lesion and may include retiform hemangioendothelioma, epithelioid hemangioendothelioma, spindle cell hemangioma, conventional angiosarcoma (low and even high grade), lymphangioma circumscriptum and areas simulating an arteriovenous malformation. References Dabska M. Malignant endovascular papillary angioendothelioma of the skin in childhood: Clinicopathologic study of 6 cases. Cancer 1969; 24: 503-510 Fanburg-Smith JC, Michal M, Partanen TA, et al. Papillary intralymphatic angioendothelioma (PILA): a report of twelve cases of a distinctive vascular tumor with phenotypic features of lymphatic vessels. Am J Surg Pathol 1999; 23: 1004-1010. Calonje, E., Fletcher, C.D.M., Wilson–Jones, E. & Rosai, J. Retiform hemangioendothelioma: a distinctive form of low–grade angiosarcoma delineated in a series of 15 cases. Am J Surg Pathol 1994; 18: 115–125. Dufau JP, Pierre C, De SaintMaur PP, et al. Hemangioendothelioma retiforme. Ann Pathol 1997; 17: 47-51. Fukunaga M, Endo Y, Masui F et al. Retiform haemangioendothelioma. Virchows Arch 1996; 428: 301-304. Duke D, Dvorak AM, Harrist TJ, et al. Multiple retiform hemangioendotheliomas. A low grade angiosarcoma. Am J Dermatopathol 1996; 18: 606-610. Mentzel T, Stengel B, Katenkamp D. Retiform hemangioendothelioma. Clinico-pathologic case report and discussion of the group of low grade malignancy vascular tumors. Pathologe 1997; 18: 390-394. Nayler SJ, Rubin BP, Calonje E, Chan JK, et al. Composite hemangioendothelioma: a complex, low-grade vascular lesion mimicking angiosarcoma.Am J Surg Pathol 2000; 24: 352-361. Reis-Filho JS, Paiva ME, Lopes JM. Congenital composite hemangioendothelioma: case report and reappraisal of the hemangioendothelioma spectrum. J Cutan Pathol 2002; 29: 226-231.