BOX 42 Clinical Presentations of Orbital Metastases

I. The primary tumor is removed, but within a few months metastases develop.

II. Metastases are already present when the primary tumor is first detected.

III. Metastases appear first, and the primary lesion remains occult.

IV. The primary tumor is removed, and metastases develop several years later.

V. Metastases regress after removal of the primary tumor.

ovary. The evaluation of these patients is facilitated by higher resolution image analysis and available serological tests. The diagnostic procedure when a metastatic orbital tumor is suspected is fine-needle aspiration or incisional biopsy.47 The use of immunohistochemical techniques is required for confirmation or identification of the primary tumor in case of an unknown or occult primary lesion.

The mean interval from the diagnosis of the primary tumor to the development of the ophthalmic sign or symptom is highly variable and is related to the biology of the primary tumors and the development and application of diagnostic methods and ther-apy.23 An interval of more than 3 to 5 years is expected in breast, thyroid, and prostate carcinoma, and carcinoids. Lung, renal, and gastrointestinal tumors are more frequently diagnosed after the appearance of orbital metastatic signs and symptoms and usually follow a fulminant course with short survival.

It is important to note that tumors with isolated orbital metastasis carry the best prognosis for survival. Approximately 2% of the body metastases occur in the setting of cancer of unknown primary site. The initial pathology study usually identifies four light-microscopic diagnoses including poorly differentiated neoplasm, adenocarcinoma, squamous cell carcinoma, and poorly differentiated carcinoma. The optimal management of these patients requires appropriate clinical and pathology evaluation to identify treatable subgroups, followed by the administration of specific therapy.

Metastatic melanoma to the orbit constitutes a unique situation because of the long delay from onset and treatment of the primary tumor and the first appearance of metastasis. It may manifest in one of four clinical settings: from an excised cutaneous lesion, in association with an active skin melanoma, with history or evidence of a spontaneously regressed melanoma, or from an occult primary site. Most patients present with widespread metastatic disease at the time of ocular manifestions.48 The survival after the diagnosis of metastastic disease is poor: the average time from diagnosis to death is 4 months (range 2-6 months).23 In addition, a patient with a metastastic melanoma may have had a spontaneously regressed cutaneous melanoma that was unnoticed, or an occult primary melanoma.49 This scenario most likely explains findings of metastatic melanoma without an apparent primary lesion or in an unknown primary. The long delay between the origin of the primary tumor and the first manifestation of metastatic disease may indicate a superior or more effective host-tumor im-munologic response. However, when metastatic disease develops, the survival rate of the patient does not differ among those with a concurrent growing primary tumor, spontaneously regressed melanoma, or occult primary site.50

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