Correspondence Low-grade, aggressive fibrous histiocytoma of the medial canthus
F
ibrous histiocytoma (FH) encompasses a heterogeneous group of mesenchymal tumours composed of varying proportions of fibroblastic and histiocytic elements. Here we describe the rare occurrence of FH in the medial canthus. A 26-year-old woman presented with a 5-month history of an enlarging, mildly tender, yellowish mass in the left medial canthal area (Fig. 1A). Clinically, the appearance was consistent with a noninflamed, cystic lesion, and a diagnosis of epidermal inclusion cyst was favored. Excisional biopsy revealed spindle cells occasionally in a storiform arrangement (Fig. 1B), focal vacuolated histiocytes, rare multinucleated giant cells, and prominent peripheral sclerotic collagen bundles. There was no overlying epidermis or capsule. These findings were in keeping with a benign fibrosing process. Six months later, the patient presented with a recurrent mass requiring a second biopsy. This specimen had similar features but, addition-
ally, showed a hyperplastic epidermis and 3–4 atypical mitoses in 20 high-power fields. Immunohistochemical staining was positive for smooth-muscle actin, muscle-specific actin, vimentin, and CD68. Staining for CD34, desmin, S-100, and HMB45 was negative. The diagnosis was low-grade aggressive FH of the medial canthus. There has been no further recurrence after 46 months. FH, believed to be derived from a pluripotential primitive mesenchymal cell, has been described in the orbit, eyelids, conjunctiva, episclera, limbus, cornea, and lacrimal sac. In a review of 150 cases of orbital FH, Font and Hidayat1 distinguished 3 groups: benign, locally aggressive, and malignant. Epithelioid and cellular variants of benign FH have been reported in the medial canthus.2 Four cases of canthal malignant FH have also been reported together with a review of the differential diagnosis.3 The major differential diagnosis of benign or aggressive FH in the canthal region is nodular fasciitis. Histologic and immunohistochemical findings, as demonstrated in our case, can be helpful in diagnosis; however, many overlapping features can make this distinction difficult. Some nodular fasciitis lesions show a storiform pattern, and the amount of myxoid matrix can be minimal.4 Transitional forms can make the distinction between FH and nodular fasciitis particularly difficult, if not impossible in some cases.4 REFERENCES 1. Font RL, Hidayat AA. Fibrous histiocytoma of the orbit: a clinicopathologic study of 150 cases. Hum Pathol 1982;13:199–209. 2. Morris SR, DeSousa J, Barrett AW, Malhotra R. Benign fibrous histiocytoma of the eyelid mimicking keratoacanthoma. Ophthal Plast Reconstr Surg 2007;23:73–5. 3. Khong JJ, Chen CS, James CL, et al. Malignant fibrous histiocytoma of the eyelid: differential diagnosis and management. Ophthal Plast Reconstr Surg 2005;21:103–8. 4. Weiss SW, Goldblum JR. Benign fibrous tissue tumors. In: Weiss SW, Goldblum JR, eds. Enzinger and Weiss’s Soft Tissue Tumors. 4th ed. St. Louis, Mo.: Mosby; 2001:247–64.
Fig. 1—(A) left medial canthal lesion with a noninflamed, cystic appearance. (B) Storiform pattern of fibroblasts characteristic of fibrous histiocytoma (hematoxylin and eosin, original magnification ×200). Left inset: multinucleated giant cell (hematoxylin and eosin, original magnification ×630); right inset: atypical mitosis (hematoxylin and eosin, original magnification ×630).
Choroidal melanoma in association with juxtapapillary melanocytoma
A
70-year-old Saudi man presented with a 4-month history of reduced vision in his left eye. On examination, his vision in that eye was counting fingers near the face. The left fundus showed an elevated, dark brown, round 4 mm choroidal mass, partially overlying the optic
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Michel J. Belliveau, Seymour Brownstein, David R. Jordan, Hamidreza Faraji University of Ottawa Eye Institute and The Ottawa Hospital, Ottawa, Ont. Correspondence to Seymour Brownstein, MD:
[email protected] Can J Ophthalmol 2008;43:250 doi:10.3129/i08-024
disc inferotemporally. The ultrasound showed moderate internal reflectivity and sound attenuation of a vascular mass. The findings were suggestive of melanoma. The histopathology of the enucleated globe showed a darkly pigmented peripapillary choroidal tumor with overlying retinal detachment and subretinal fluid. Bleached sections showed 2 types of cells: round-to-oval cells with abundant cytoplasm, pigment granules, and small nuclei,
Correspondence representing melanocytoma cells; and spindle B cells, representing the developing melanoma, with atypical mitotic figures (Fig. 1). No demarcation was noted between the different types of cells. The tumor invaded the adjacent optic nerve head. The diagnosis was choroidal melanoma arising in association with a pre-existing juxtapapillary melanocytoma. This was further supported by positive immunostaining with HMB45. Dendritic melanocytes derived from the neural crest are the origin of pigmented intraocular growths such as nevi, melanocytomas, and melanomas. A melanocytoma is a tumor with a characteristic darkly pigmented color that can occur anywhere in the uvea or, classically, in the optic nerve head. Loeffler and Tecklenborg1 noted enough building evidence that melanocytoma, which was regarded as a benign stationary tumor, has the potential for growth and even malignant transformation. This indicates the necessity of follow-up in these cases.2 Joffe et al.,3 in their study of 40 patients with optic disc melanocytoma, demonstrated a juxtapapillary choroidal nevus component in 47% and slight enlargement in 15%, with a follow-up period of 1 to 19 years. In 1990, Shields et al.4 clarified the malignant transformation of uveal melanocytomas in their case report of a mixed-cell
type melanoma arising from a melanocytoma of the optic disc and the juxtapapillary choroid. They believed that the case previously reported by Apple et al.5 was probably a juxtapapillary choroidal melanoma of the mixed-cell type growing over the optic nerve head. In 1992, Loeffler and Tecklenborg1 reported an optic disc melanocytoma that turned into a spindle B malignant melanoma within the peripapillary choroid over 7 years. No melanocytoma cells were seen within the choroid. Meyer et al.6 reported a typical optic disc melanocytoma with change in color and size after 5.5 years. The histopathology demonstrated spindle B melanoma cells mixed with melanocytoma cells, extending to the lamina cribrosa. They strongly recommended serial fundus photographs of melanocytoma cases. The ultrastructural features were described by Juarez and Tso.7 Our case showed mainly type 2 melanocytoma cells with indented nuclei and relatively smaller melanosomes (Fig. 2). A few macrophages with phagosomes containing irregular melanin granules were also identified. Our patient presented with vision loss and an elevated lesion suggestive of malignancy. Since there was no clinical or photographic documentation of his original melanocytoma, we suggest that there is enough evidence with histopathologic and ultrastructural changes to indicate that this is a peripapillary melanocytoma transforming into a melanoma within the inferotemporal choroid, which is the usual location, as observed by Mansour et al.2 REFERENCES
Fig. 1—Bleached section showing mixed melanocytoma cells and spindle B melanoma cells (hematoxylin and eosin, original magnification ×200).
1. Loeffler KU, Tecklenborg H. Melanocytoma-like growth of a juxtapapillary malignant melanoma. Retina 1992;12:29–34. 2. Mansour AM, Zimmerman L, LaPiana FG, Beauchamp GR. Clinicopathological findings in a growing optic nerve melanocytoma. Br J Ophthalmol 1989;73:410–5. 3. Joffe L, Shields JA, Osher RH, Gass JDM. Clinical and followup studies of melanocytomas of the optic disc. Ophthalmology 1979;86:1067–83. 4. Shields JA, Shields CL, Eagle RC Jr, Lieb WE, Stern S. Malignant melanoma associated with melanocytoma of the optic disc. Ophthalmology 1990;97:225–30. 5. Apple DJ, Craythom JM, Reidy JJ, Steinmetz RL, Brady SE, Bohart WA. Malignant transformation of an optic nerve melanocytoma. Can J Ophthalmol 1984;19:320–5. 6. Meyer D, Ge J, Blinder KJ, Sinard J, Xu S. Malignant transformation of an optic disc melanocytoma. Am J Ophthalmol 1999;127:710–4. 7. Juarez CP, Tso MO. An ultrastructural study of melanocytomas (magnocellular nevi) of the optic disk and uvea. Am J Ophthalmol 1980;90:48–62.
Hind M. Alkatan, Saba Al-Rashaed King Khaled Eye Specialist Hospital, Riyadh, Kingdom of Saudi Arabia Fig. 2—Electron microscopy of a melanocytoma cell with indented nucleus and melanosomes (original magnification ×3800).
Correspondence to Hind Alkatan, MD:
[email protected] Can J Ophthalmol 2008;43:250–1 doi:10.3129/i08-019 CAN J OPHTHALMOL—VOL. 43, NO. 2, 2008
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