Sentinel Lymph Node Biopsy for Conjunctival and Eyelid Malignancies

Abstract

Sentinel lymph node (SLN) biopsy is a minimally invasive technique that aims to diagnose microscopic metastasis in the regional lymph nodes The value of SLN biopsy has been widely studied for cutaneous melanoma, breast carcinoma, as well as other solid cancers. We have modified SLN biopsy techniques for conjunctival and eyelid tumors, because many of the cancers of the ocular adnexa such as conjunctival melanoma and sebaceous cell carcinoma have the predilection for regional lymph nodes as the site of first metastasis An SLN biopsy technique using both isosulfan blue dye (0.2 cc volume) and technetium (0.3 mCi in 0.2 cc volume) was initially used by our group. A smaller volume of these tracers is used than in other anatomic sites, in order to prevent excessive ballooning up of the conjunctiva and the spread of the tracer to non-specific quadrants of the conjunctiva. We have abandoned the use of the isosulfan blue dye in the latter part of our trial as none of the SLNs was found to be blue. We believe this is due to the much smaller volume of the isosulfan dye used for ocular adnexal lesions and the rapid transit of the dye through the lymphatics in the head and neck region The regional lymph nodes at the greatest risk for metastasis from conjunctival and eyelid cancers are the parotid, preauricular, and submandibular lymph nodes Our experience suggests that SLN biopsy can be safely performed for conjunctival and eyelid cancers and is associated with very few side effects.Only three out of 27 patients enrolled in our trial have had a temporary weakness of the marginal mandibular branch of the facial nerve as a result of sentinel lymph node biopsy in the parotid region. Each has had spontaneous resolution of the facial nerve paresis within a few weeks. Blue discoloration of the ocular surface or periocular skin has not been observed in any of the patients enrolled in our trial so far. No patient in our trial has experienced an anaphylactic shock from the blue dye, although this has been reported in other studies of SLN biopsy Two out of 27 patients enrolled in our trial — both with a diagnosis of conjunctival melanoma — have had a histologically positive sentinel lymph node which was clinically (on physical examination) and radiographically negative. This validates the concept that SLN biopsy can identify patients who may harbor microscopic nodal metastasis, thus offering the opportunity for additional treatments earlier in their course Two out of 27 patients who had a “negative” SLN later developed clinically detectable metastasis within the regional lymph nodes, suggesting a false negative rate of about 8% Careful evaluation of regional lymph nodes is indicated in all patients with conjunctival melanoma, eyelid melanoma, eyelid sebaceous cell carcinoma,Merkel cell carcinoma, or other ocular adnexal cancers with a tendency to metastasize to the regional lymph nodes. Ultrasonography and computed tomography should be utilized at baseline and throughout the course of the disease. If these radiographic modalities fail to find a positive node at baseline, consideration should be given to sentinel lymph node biopsy at the time of initial diagnosis of these ocular adnexal cancers