Phakomatous Choristoma

Abstract

Phakomatous choristoma is a rare congenital lesion of the eyelid that can be clinically and/or histologically mistaken for a cyst, cutaneous adnexal neoplasm, or an ocular adnexal oncocytoma. Only 13 such cases have been previously described, mostly in the English language ophthalmic literature. Zimmerman reported the first case in 1971 and proposed the lesion to be of lenticular anlage origin, a theory that has been widely accepted. We report an additional case occurring in an 8-week-old male infant with a firm nodule of the right lower eyelid that was present since birth. A 15 x 12 x 2 mm circumscribed solid nodule with a homogenously white cut surface was surgically excised. Histologically, this lesion was comprised of cuboidal cells forming cystically dilated and irregularly branched ducts and cords within a densely fibrotic stroma. Also present were eosinophilic basement membranelike material, psammoma body-like calcifications and intraluminal degenerated ghost cells. The immunohistochemical profile of the epithelial cells included strong immunoreactivity for vimentin, focal weak staining for S-100, and negative staining for cytokeratin, epithelial membrane antigen, synaptophysin, and chromogranin. The irregularity of the ducts and cords of epithelial cells within the densely fibrotic stroma resembled an infiltrative neoplasm of cutaneous adnexal or lacrimal duct origin. However, the site of involvement, the peculiar basement membrane material, ghost cells, and immunohistochemical profile were features that helped to distinguish phakomatous choristoma from an infiltrative carcinoma. The correct identification of this lesion is essential to avoid an aggressive surgical excision, thus sparing the eyelid and lacrimal system. The purpose of this article is to bring attention to this rare entity, because it has not been described in either the dermatology or dermatopathology literature and furthermore, is not mentioned in any of the major dermatopathology texts.

Phakomatous choristoma of the eyelid

“…Immunohistochemical studies were performed in eight of the reported phakomatous choristomas and revealed positivity for S-100 in all cases [2,3,7,12,13,14,15,16] and positivity for vimentin in seven cases [2,3,7,12,13,14,16]. The here reported case showed the same immunohistochemical results.…”

“…The irregularity of the ducts and cords of epithelial cells within the densely fibrotic stroma resembles an infiltrative neoplasm of cutaneous adnexal or lacrimal duct origin [2]. However, the site of involvement, the peculiar basement membrane material and the similarity to "bladder cells" are features that help to distinguish phakomatous choristoma from an infiltrative carcinoma [2]. Immunophenotypically phakomatous choristoma can be distinguished from cutaneous adnexal tumors by positivity for S-100 and vimentin and negative staining for cytokeratin, which would be positive in adnexal tumors.…”

Phakomatous Choristomas: A Case Report and Review of Literature

“…In the 28 published cases, the age at time of surgical excision ranged from 2 weeks to 13 months, with the average being 4.7 months (interquartile range, 2 months–5.5 months). 3–26 There was a slight predominance of PC occurring in males (68%). The mass primarily involved the lower eyelid in 25 cases, with postseptal extension in 16 of the cases.…”

“…3–26 It is commonly described as a firm palpable mass presenting at birth, most commonly affecting the lower eyelid nasally with inferomedial orbital extension. 3–26 The table describes the clinical and histological characteristics, management, and outcomes of all published cases in the literature. In the 28 published cases, the age at time of surgical excision ranged from 2 weeks to 13 months, with the average being 4.7 months (interquartile range, 2 months–5.5 months).…”

“…There have been 28 cases of PC reported in the literature, with only 14 reports in the United States. 3–26 It is commonly described as a firm palpable mass presenting at birth, most commonly affecting the lower eyelid nasally with inferomedial orbital extension. 3–26 The table describes the clinical and histological characteristics, management, and outcomes of all published cases in the literature.…”