Medial canthus retiform hemangioendothelioma.

Retiform hemangioendothelioma (RH) is a distinct entity in the spectrum of vascular tumors with a high local recurrence rate. It is considered a low-grade, well-differentiated cutaneous angiosarcoma with low metastatic potential. We report here for the first time a case of medial canthus recurrent RH. It may be helpful in our practice to include RH as a differential diagnosis of eyelid lesions. It is noteworthy that the progressive course and recurrence tendency of RH might be misdiagnosed as angiosarcoma or basal cell carcinoma (BCC), if not expected and carefully evaluated by the pathologist.

Retiform hemangioendothelioma (RH) is a very rare vascular lesion that was first described by Calonje et al., in 1994.[1] Despite being mostly reported as an acquired skin lesion that affects young and middle-aged adults, it may also develop as a congenital vascular lesion.[2] RH shows limb predilection, but is occasionally reported in the trunk, penis, or scalp.[3] Although it frequently recurs, distant metastases are exceedingly rare.[4] In our practice, we may overlook RH as a differential diagnosis of vascular eyelid lesions, as RH has not been reported in the periocular area.

Case Report

A 9-year-old girl presented with a skin lesion in the right medial canthus area towards the nasal bridge. It was located at the margin of a skin graft that had been used to reconstruct a medial canthus skin defect. According to her medical history, an antedated lesion was noted as a pinkish, painless, elevated lesion with a slightly larger size than the current one, which started to develop when the patient was 4-year-old. The antedated lesion was excised with reconstruction, in a procedure that was done outside the country 3 years earlier. The parents were told that it was a basal cell carcinoma (BCC); however, neither the histopathology report nor a specimen block was available for review. There was no clinical history of other dermal lesions or radiotherapy.

The current lesion was a painless, slightly raised, indurated and purple-colored skin lesion which measured 8 × 4 mm with a central depression adherent to the underlying structures [Fig. 1a]. It had grown slowly over a 6-month period, but was later excised with safety margins and reconstruction. A new painless, raised, purple-colored skin lesion measuring 3 × 3.5 mm did, however, appear 1 year later on the medial aspect of the recently used skin graft [Fig. 1b], and a complete excision was performed. Notably, the donor skin graft was inspected carefully for any lesion before harvesting. No other skin lesions or cardiovascular complications were detected, and the child was otherwise normal. She had unremarkable ocular examination with 20/20 visual acuity in both eyes.

Figure 1

Retiform hemangioendothelioma. (a) Shows raised, indurated, purple-colored skin lesion with central depression in the medial canthus area of the right eye towards nasal bridge. (b) Shows raised, purple colored skin lesion on the medial aspect of the right upper eyelid at the margin of the recently used skin graft (arrow)

The histopathological study of both lesions showed numerous, elongated, thin-walled blood vessels resembling the rete testis. The vessels were lined by plump endothelial cells with high nuclear/cytoplasmic ratio, but without significant atypia or mitotic figures. The stroma showed small groups of scattered lymphocytic inflammatory infiltration. Immunohistochemistry studies were positive for CD31, CD34, factor VIII-related antigen, bound Ulex europaeus agglutinin (UEA), and partially positive for D2-40; but were negative for CD61, cytokeratin, vascular endothelial growth factor receptor 3 (VEGFR-3), and human herpes virus-8 (HHV-8), all of which confirmed the vascular origin of this tumor [Fig. 2a–c].

Figure 2

Histopathology and immunohistochemistry studies. (a) Photomicrograph showing a group of elongated and small-sized blood vessels infiltrating between skeletal muscle fibers and fat. This arrangement can result in diagnostic challenge for pathologists, especially in frozen section diagnosis (hematoxylin and eosin stain (H and E), 100) (b) Photomicrograph showing retiform and elongated vessels with “slit-like” lumens (arrow head; H and E, ×400). (C) Shows strong positive staining with CD34 (endothelial marker)

Based on the above described histologic and immunohistochemical features, the diagnosis of RH was established. There were no further recurrences over the last 6 years of follow-up.

Discussion

RH is a very rare low-grade cutaneous angiomatous neoplasm that may occur on top of local radiotherapy, lymphedema, or HHV-8.[14] It has a local recurrence tendency and low metastatic potential, yet an assumed single tumor-related death has been also reported.[567] The limbs and trunk are the most common locations reported in the literature; nevertheless, the scalp, skull, and penis are involved in some cases.[5] RH may develop in different age groups without gender preference; however, the youngest reported age was 9 years.[6] Notably, Serel et al., reported a congenital case which presented at the late age of 27 years.[8]

Clinically, RH frequently presents as a solitary, painless, raised, indurated, and slow-growing plaque or nodule; however, multiple and/or painful lesions have also been reported.[17] It has a brown to violaceous center and pale peripheral area which may be surrounded by an ecchymotic ring.[5] Involvement of the skin with deeper extension to the subcutaneous tissue or muscle layer is the general rule.[1] As the clinical picture is not specific, the typical histopathological features are essential for the diagnosis. Microscopically, the distinctive arborizing, thin-walled blood vessels resembling rete-testis with plump endothelial lining are characteristic features.[1] The neoplastic cells stain for vascular markers (CD31, CD34, and von Willebrand factor) with stronger staining for CD34 than other vascular markers.[1] RH also stains for factor VIII-related antigen and bound UEA.[9] The lymphocytes within the stroma are positive for pan-T cell markers and a minority of lymphocytes stain for CD20 (B cell marker).[1]

Our case represents recurrent medial canthus RH without any predisposing factor. Despite having a different clinical presentation, all consecutive lesions manifested as pinkish elevated lumps, infiltrating purple-colored plaques and solitary papule-like tumors, which are frequent clinical features of RH.[15] Because of the diversity and nonspecific clinical features, we had considered BCC, Dabska tumor, Kaposiform hemangioendothelioma, and angiosarcoma as differential diagnoses.

Because BCC has not been reported in an otherwise normal child, we were not confident of the nature of the previously excised lesion; that is, whether it was BCC or RH misdiagnosed as BCC. The “plump and hobnail-like hemangioendothelioma” can also be seen in cases of Dabska tumor.[7] Of note, RH may stain partially positive for D2-40, but it does not usually express VEGR-3.[10] Kaposiform hemangioendothelioma can mimic RH, as it may involve the skin during infancy and early childhood, despite typically presenting as a retroperitoneal tumor with abdominal mass, jaundice, or ascites. Kaposiform hemangioendothelioma shows spindle cells arranged in criss-crossing fascicles interspersed with capillaries, which stains positive for CD31 and CD34, but negative for factor VIII-related antigen.[711] Tufted angioma is a rare benign vascular lesion that can also mimic RH and presents before the age of 5 years. Microscopic examination helps in differentiation, as it reveals lobules of capillary-sized blood vessels lined by plump oval nuclei, which were distributed in a cannonball pattern and infiltrated deeply between the muscle.[12] Angiosarcoma can present during childhood; however, the absence of clusters of neoplastic cells with nuclear pleomorphism, mitotic activity and vacuolated endothelial cells that stain with cytokeratin can differentiate between RH and angiosarcoma.[611]

The case reported herein has unique features, as it represents the youngest age ever reported among acquired RH, and an unusual location, being the first reported periocular RH. As recurrence and extensive involvement of the skin and deeper structures are challenging features of this angiomatous lesion which could be confused with frank malignant lesions, ophthalmologists should be aware of such diagnosis. The optimal treatment of RH is wide surgical excision with safety margin; however, radiotherapy is effective in the rare cases of lymph node metastasis.[1]