Pediatric Dermatology Vol. 32 No. 3 405–409, 2015
Phakomatous Choristoma in a 10-Week-Old Boy: A Case Report and Review of the Literature Ryan C. Romano, D.O.,* Patrick McDonough, M.D.,† Diva R. Salomao, M.D.,* and Karen J. Fritchie, M.D.* *Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, †Department of Pathology, Prevea Clinic, Green Bay, Wisconsin
Abstract: Phakomatous choristoma (PC) is a rare benign congenital lesion of lenticular anlage. It presents in young patients as a firm subcutaneous mass in the medial eyelid or orbit and may raise clinical concern for neoplasms such as rhabdomyosarcoma, but its histopathology is distinct, consisting of dense collagenous stroma and eosinophilic cuboidal epithelial cells forming nests, tubules, cords, or pseudoglands. We present a case of PC in a 10-week-old boy to illustrate the unique clinical, histopathologic, and immunophenotypic features of this condition and to reaffirm that familiarity with this rare entity aids accurate diagnosis.
Phakomatous choristoma (PC) is a rare benign proliferation of ectopic lens tissue, with few cases reported in the English literature since its initial description in 1971 (1–14). Although there is consensus that this lesion arises from lenticular anlage, numerous theories have been proposed regarding its pathogenesis. PC presents in children as a firm subcutaneous mass in the medial inferior eyelid or orbit. Although the clinical differential diagnosis includes benign entities such as cutaneous adnexal tumors and dermoid cysts, the age of the patient and location of the mass may also raise concern regarding malignancies such as rhabdomyosarcoma. The histopathology of PC is unique, allowing pathologists who
are familiar with it to distinguish it easily from malignant neoplasms. Surgical excision is curative, even when incomplete, and correct diagnosis is vital to avoid inappropriately aggressive intervention. CASE REPORT A healthy 10-week-old boy was evaluated for a left infraorbital subcutaneous mass that had been present and slowly enlarging since birth. His prenatal history was unremarkable. His 2-week peri- and neonatal hospitalization included initial placement in the neonatal intensive care unit for monitoring of apneic episodes. His medical course was otherwise
Address correspondence to Karen J. Fritchie, M.D., Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street SW, Hilton 11, Rochester, MN 55905, or e-mail: [email protected]. This case was presented in poster form at the 17th Annual Joint Meeting of the International Society of Dermatopathology, Denver, Colorado, March 19–20, 2014. DOI: 10.1111/pde.12493
© 2014 Wiley Periodicals, Inc.
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unremarkable after discharge. At 2 months of age he underwent magnetic resonance imaging of the lesion, which showed a well-defined, mildly enhancing 1.1-cm 9 1.1-cm 9 0.7-cm nodule approximating the inferior medial margin of the left ocular globe (Fig. 1). There was no radiologic evidence of bony involvement. The patient underwent incisional biopsy for diagnosis, at which time the lesion was 75% excised. The remainder of the mass was unresectable because of nerve and muscle (inferior rectus) involvement. Histopathologic examination demonstrated a proliferation of cuboidal cells lining glandular-type spaces filled with eosinophilic proteinaceous material embedded in a loose fibromyxoid background (Fig. 2). No cytologic atypia was identified in the cuboidal or spindle cell component. Immunohistochemistry showed strong staining of the cuboidal cells with S-100 and glial fibrillary acidic protein (Fig. 3). Cytokeratins (OSCAR, AE1/AE3, CK 5/6), desmin, HMB-45, FLI-1, CD31, synaptophysin, and chromogranin were negative. There has been no further enlargement of residual tumor since the subtotal resection. DISCUSSION Phakomatous choristoma is a rare benign congenital lesion composed of aberrantly displaced optic lens
Figure 1. Magnetic resonance imaging demonstrating a well-defined, mildly enhancing 1.1-cm left infraorbital subcutaneous nodule that is hypointense to brain parenchyma and shows no fluid signal.
tissue that presents as an inferonasal eyelid or orbital mass in young children (1). Although Zimmerman (2) is credited with first describing this entity in 1971, proposing in his report that this was a tumor of lenticular origin, it is likely that, before 1971, lesions such as this were misclassified or given a descriptive diagnosis as chronicled in the historical perspective offered by Szyfelbein et al (3). There is no apparent significant sex or ethnic predilection with PC (1,4,5). It is generally present at birth, although in some cases it may not develop until shortly thereafter (1). It presents as a firm, slowly enlarging, subcutaneous mass or nodule that is typically
Phakomatous Choristoma in a 10-Week-Old Boy: A Case Report and Review of the Literature Ryan C. Romano, D.O.,* Patrick McDonough, M.D.,† Diva R. Salomao, M.D.,* and Karen J. Fritchie, M.D.* *Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, †Department of Pathology, Prevea Clinic, Green Bay, Wisconsin
Abstract: Phakomatous choristoma (PC) is a rare benign congenital lesion of lenticular anlage. It presents in young patients as a firm subcutaneous mass in the medial eyelid or orbit and may raise clinical concern for neoplasms such as rhabdomyosarcoma, but its histopathology is distinct, consisting of dense collagenous stroma and eosinophilic cuboidal epithelial cells forming nests, tubules, cords, or pseudoglands. We present a case of PC in a 10-week-old boy to illustrate the unique clinical, histopathologic, and immunophenotypic features of this condition and to reaffirm that familiarity with this rare entity aids accurate diagnosis.
Phakomatous choristoma (PC) is a rare benign proliferation of ectopic lens tissue, with few cases reported in the English literature since its initial description in 1971 (1–14). Although there is consensus that this lesion arises from lenticular anlage, numerous theories have been proposed regarding its pathogenesis. PC presents in children as a firm subcutaneous mass in the medial inferior eyelid or orbit. Although the clinical differential diagnosis includes benign entities such as cutaneous adnexal tumors and dermoid cysts, the age of the patient and location of the mass may also raise concern regarding malignancies such as rhabdomyosarcoma. The histopathology of PC is unique, allowing pathologists who
are familiar with it to distinguish it easily from malignant neoplasms. Surgical excision is curative, even when incomplete, and correct diagnosis is vital to avoid inappropriately aggressive intervention. CASE REPORT A healthy 10-week-old boy was evaluated for a left infraorbital subcutaneous mass that had been present and slowly enlarging since birth. His prenatal history was unremarkable. His 2-week peri- and neonatal hospitalization included initial placement in the neonatal intensive care unit for monitoring of apneic episodes. His medical course was otherwise
Address correspondence to Karen J. Fritchie, M.D., Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street SW, Hilton 11, Rochester, MN 55905, or e-mail: [email protected]. This case was presented in poster form at the 17th Annual Joint Meeting of the International Society of Dermatopathology, Denver, Colorado, March 19–20, 2014. DOI: 10.1111/pde.12493
© 2014 Wiley Periodicals, Inc.
405
406 Pediatric Dermatology Vol. 32 No. 3 May/June 2015
unremarkable after discharge. At 2 months of age he underwent magnetic resonance imaging of the lesion, which showed a well-defined, mildly enhancing 1.1-cm 9 1.1-cm 9 0.7-cm nodule approximating the inferior medial margin of the left ocular globe (Fig. 1). There was no radiologic evidence of bony involvement. The patient underwent incisional biopsy for diagnosis, at which time the lesion was 75% excised. The remainder of the mass was unresectable because of nerve and muscle (inferior rectus) involvement. Histopathologic examination demonstrated a proliferation of cuboidal cells lining glandular-type spaces filled with eosinophilic proteinaceous material embedded in a loose fibromyxoid background (Fig. 2). No cytologic atypia was identified in the cuboidal or spindle cell component. Immunohistochemistry showed strong staining of the cuboidal cells with S-100 and glial fibrillary acidic protein (Fig. 3). Cytokeratins (OSCAR, AE1/AE3, CK 5/6), desmin, HMB-45, FLI-1, CD31, synaptophysin, and chromogranin were negative. There has been no further enlargement of residual tumor since the subtotal resection. DISCUSSION Phakomatous choristoma is a rare benign congenital lesion composed of aberrantly displaced optic lens
Figure 1. Magnetic resonance imaging demonstrating a well-defined, mildly enhancing 1.1-cm left infraorbital subcutaneous nodule that is hypointense to brain parenchyma and shows no fluid signal.
tissue that presents as an inferonasal eyelid or orbital mass in young children (1). Although Zimmerman (2) is credited with first describing this entity in 1971, proposing in his report that this was a tumor of lenticular origin, it is likely that, before 1971, lesions such as this were misclassified or given a descriptive diagnosis as chronicled in the historical perspective offered by Szyfelbein et al (3). There is no apparent significant sex or ethnic predilection with PC (1,4,5). It is generally present at birth, although in some cases it may not develop until shortly thereafter (1). It presents as a firm, slowly enlarging, subcutaneous mass or nodule that is typically
