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Vital staining of squamous cell carcinoma of the conjunctiva using toluidine blue

2006; Wiley; Volume: 84; Issue: 6 Linguagem: Inglês

10.1111/j.1600-0420.2006.00739.x

1600-0420

Yuichi Kaji, Takahiro Hiraoka, Tetsuro Oshika,

Ear and Head Tumors

A 74-year-old man was referred to the hospital with a diagnosis of chronic conjunctivitis of the right eye that was resistant to topical and systemic steroid therapies. Slit-lamp examination revealed a conjunctival tumorous lesion suggestive of squamous cell carcinoma (SCC) or carcinoma in situ (CIS) (Fig. 1A). Biopsy results at three points of the lesion were compatible with CIS, although the possibility of SCC still remained (Fig. 1B). The following week, the entire conjunctival lesion was surgically removed. (A) Slit-lamp examination revealed reddish conjunctival tumorous lesion with irregular margin and surface. These findings were compatible with squamous cell carcinoma (SCC) or carcinoma in situ (CIS) of the conjunctiva. (B) Biopsy of the conjunctival lesion was compatible with CIS. (Original magnification × 100.) (C) The margin of the SCC was obscure under a surgical microscope. (D) Toluidine blue solution was dropped over the conjunctiva. (E) The area of the SCC was stained purple and became clearly visible. (F) The staining remained even after subconjunctival injection of xylocaine. Before the surgery, 0.05% of toluidine blue (Sigma, St Louis, MO, USA) dissolved in saline was prepared and sterilized. Although the conjunctival tumorous lesion was easily recognizable by slit-lamp examination, the border of the lesion was obscure under the surgical microscope (Fig. 1C). The toluidine blue solution was dropped over the conjunctiva (Fig. 1D). Within a minute, the surface of the conjunctival tumorous lesion was stained purple but the normal conjunctiva was not (Fig. 1E). Thus, the complicated border could be seen easily. In addition, some islet-like protrusions of the conjunctival tumorous lesion that might otherwise have been overlooked were clearly visible. Furthermore, staining of the conjunctival lesion with toluidine blue remained even after subconjunctival injection of 2% xylocaine (Fig. 1F) and gentle scrubbing with a methylcellulose sponge. With the aid of the toluidine blue vital stain, we were able to precisely remove the conjunctival tumorous lesion en bloc and reconstruct the remaining conjunctiva successfully. Histological examination was compatible with SCC with breach of the basement membrane. In addition, the border of the excised surgical specimen was negative for carcinoma cells in the serial sections. The management of SCC or CIS of the conjunctiva varies with the extent of the lesion. In general, surgical removal with cryotherapy and chemotherapy with topical mitomycin C, 5-fluorouracil, or interferon are recommended for the treatment of SCC or CIS of the conjunctiva (Shields & Shields 2004). Although topical chemotherapy has gained in popularity because of its high success rates, surgery is still the first choice of treatment in SCC or CIS of the conjunctiva, especially when the tumorous lesion is relatively small (Yang & Foster 1997; Shields & Shields 2004). To remove an SCC or CIS of the conjunctiva completely and reconstruct the remaining conjunctiva successfully, surgeons should locate the margins of the conjunctival lesion during the surgery. However, it is sometimes difficult to locate the area of the tumorous lesion under a surgical microscope. Vital staining using dyes such as Lugol's solution and toluidine blue are widely used to visualize tumorous lesions in colposcopy and endoscopy (Schiller 1933; Richart 1963; Giler et al. 1976). Toluidine blue is widely used in oesophageal and gastrointestinal endoscopy (Richart 1963; Giler et al. 1976). In general, 0.2–1% solution of toluidine blue is used for vital staining in endoscopy (Richart 1963; Giler et al. 1976). However, 0.05% toluidine blue solution was sufficient to visualize the location of SCC in the conjunctiva. Lower concentrations of toluidine blue will reduce its potential toxic side-effects after light exposure (Tremblay et al. 2002). We have confirmed that toluidine blue staining was negative in cases of pterygium, pinguecula, papilla, follicle and dry eye. This means that vital staining with toluidine blue can be used to detect SCC or CIS of the conjunctiva. In conclusion, vital staining of the conjunctiva with toluidine blue was effective in detecting the precise location of the SCC. This technique will make it easier to remove an SCC completely and reconstruct the remaining conjunctiva successfully. This work was supported by the Ministry of Education, Science, Sports and Culture, Japan, through a Grant-in-Aid for Young Scientists (grant no. 16791042).