A valuable test for malignancy of orbital tumors

SECTION biopsy, the removal of the whole or a part of the mass, is considered the “gold standard” in the diagnosis of orbital lesions. An incisional or excisional biopsy is performed depending on the size of the mass. This diagnostic and therapeutic procedure is selected for tumors suspected to be malignant. Fine-needle aspiration biopsy (FNAB) or aspiration-biopsy cytology is widely used for morphologic diagnosis of tumors.

1 It has the advantage of possibly obviating major surgeries. It requires the removal of a sample of cells using a fine needle to predict the nature of the entire lesion, assuming that the lesion is homogenous. It is a cytologic rather than a histologic technique. It has other advantages: it is easy to perform and does not require extensive preparations such as hospitalization or anesthesia, results are fast, and costs are lower. Reported complications include pain and anxiety, minor bleeding, vasovagal reaction, seizures, nerve damage, local anaphylaxis, and infection.

1 In this study we determined the effectiveness of FNAB in detecting malignancy in orbital lesions compared with section biopsy. We determined its sensitivity, specificity, and positive predictive value.

METHODOLOGY
Patients with orbital lesions who underwent FNAB at the Orbit Section of the Department of Ophthalmology East Avenue Medical Center from January 2001 to June 2003 were included into the study. Those who did not undergo section biopsy, or had poor yield or hemorrhagic smears were excluded. FNAB was performed as follows: Computed-tomography (CT) plates were examined and the position of the mass noted. The skin was cleansed with povidone iodine. No anesthetic was used. A gauge 23, 1.5-inch needle attached to a 10 cc disposable plastic syringe was carefully introduced into the lesion, avoiding blood vessels. After entering the mass, suction was applied and maintained with the syringe. The needle was moved in and out, in a cutting motion within the lesion, to obtain adequate sample. At the conclusion of the procedure, the suction was released, and the needle was pulled straight out. Sterile dressing was applied on the puncture site and pressure applied. Aspirates were smeared on a glass slide and fixed with 95% ethyl alcohol. Slides were stained with Papanicolau and analyzed under a microscope. A section biopsy was subsequently done under standard techniques. The cytologic results were correlated with the histologic results. Different pathologists who were blinded as to study lesions read the cytologic and histologic smears.

RESULTS
Thirty-three patients (20 males and 13 females, ages 11 months to 71 years) underwent FNAB but only 23 whose smears had high yield of cells were included. Excluded were 2 with poor yield smears, 3 hemorrhagic smears, and 5 without section biopsies, two of whom presented with pyogenic granuloma that responded to antibiotics.

Table 1 shows the comparison between the cytologic diagnosis from FNAB and the histologic diagnosis from the section biopsy. Eight of the cytologic results showed malignancy with one false negative. On the other hand, all 15 cases that had negative malignancy on section biopsy also showed negative on FNAB.

Results showed that FNAB is 87.5% sensitive and 100% specific, with a positive predictive value of 100% (Table 2). When compared with corresponding incisional biopsy using Fishers Exact Test, no statistical difference was found between FNAB and section biopsy in detecting ocular malignancy (p < 0.05).

DISCUSSION
FNAB is a well-recognized technique in the diagnosis of tumors of the head, neck, lung, in various abdominal and prostatic tumors, and more recently, in tumors of the bone and eyelid.

2 Remulla, et.al. found that FNAB was a useful technique in the diagnosis of retinoblastoma,

3 which confirmed findings by Das et al. in 3 cases of retinoblastoma in children.

4 These studies showed that FNAB is a useful tool in the diagnosis of orbital tumors, which can be performed as an outpatient procedure with minimal discomfort and cost to the patient. Cytologic results from the biopsy give a preliminary idea of whether the lesion is malignant or benign so that appropriate treatment can be planned before contemplating a more invasive procedure. Our results showed that FNAB has high sensitivity and specificity for detecting ocular malignancy and that the concordance between the two procedures is good though the sample size is small. Other studies have shown similar results.

2-5 Caution, however, must be exercised in the interpretation of cytologic results of FNAB.

2 The best indication for FNAB is detection of malignant orbital disease.

5 It is not helpful in tumors or inflammatory disease with a high fibrous content.

5 Lesions that are suspected pseudotumors are not recommened for FNAB since they are notoriously difficult to distinguish from well- differentiated lymphocytic malignant lymphoma even in histologic sections.

5 For instance, one patient in this series showed cytomorphologic findings consistent with a lymphoproliferative disorder, which was confirmed with a histologic diagnosis of malignant lymphoma (Figure 1). However, 5 smears with the same cytomorphologic