Self assessment for Pathologists
Summary:
We offered this self-assessment just for fun. We will consider expanding this section with more questions. We may also consider offering continuing medical education credits in the future.
Please contact us with your feedback and questions!
Question 1: Temporal arteritis
Question 2: Choroidal melanoma and prognosis
Question 3: Conjunctival melanoma and prognosis
Question 4: Ocular cancers
Question 5: Corneal transplant specimens
Question 1: Temporal arteritis
The situation presented in the question is common and often frustrating for the pathologist. If an ophthalmologist does a temporal artery biopsy, if the biopsy is adequate in length, and if the specimen is sampled completely to rule out skip lesions ...
... and if, after all this care, there is no arteritis, then why would the ophthalmologist still treat the patient with corticosteroids? If they were going to treat the patient anyway, why do the biopsy?
Good questions!
Ophthalmologist worry about temporal arteritis because patients may become bilaterally blind (irreversibly!) within hours if not treated. They may perform the biopsy because they want confirmation of their clinical impression. Elderly patients with temporal arteritis may require long-term corticosteroid treatment with all of the complications that such treatment may involve. If pathologist can confirm the clinical impression of temporal arteritis, the ophthalmologist is more likely to "stay the course" through long-term medical treatment.
Therefore, if the pathologist's diagnosis does not show temporal arteritis, the ophthalmologist may either treat the patient on the basis of clinical impression (and laboratory data) or may biopsy the contralateral side for histologic confirmation. Either way, the ophthalmologist is likely to begin treatment ... despite the pathologist's diagnosis ... if the history, physical examination, and sedimentation rate/c-reactive protein indicate temporal arteritis.
Question 2: Choroidal melanoma and prognosis
The prognosis of uveal melanoma (iris, ciliary body, and choroid) is related to many factors.
Extraocular extension (spread beyond the eye) is a poor prognostic sign.
Location may be prognostically significant. Tumor confined to the iris tend to have a more favorable prognosis than those of the choroid or ciliary body.
There are some key differences between cutaneous melanoma and uveal melanoma. The key prognostic dimension for uveal melanoma is the measurement of the basal diameter ... the tumor in contact with the sclera ... not the height of the tumor. Also, unlike cutaneous melanoma, a large number of tumor infiltrating lymphocytes in uveal melanoma is associated with a poor prognosis.
Cell type (the more epithelioid cells, the worse the prognosis) and estimations of cell proliferation are key prognostic features.
Recently, the presence of a highly patterned microcirculation forming networks of interconnected loops has been associated with death from metastatic melanoma. The generation of this distinctive patterned microcirculation is a major focus of our research.
Question 3: Conjunctival melanoma and prognosis
The main determinant of conjunctival melanoma is the depth of invasion. The conjunctival substantia propria is not compartmentalized as is the dermis in the skin. It is therefore not possible to speak of "levels of invasion" in the conjunctiva. The pathologist should, however, indicate if tumor has encroached into dense fibrous connective tissue at the base of the lesion (such tissue may represent the superficial layers of sclera).
The major determinant of prognosis is the depth of invasion (less than 0.8 mm has a relatively favorable prognosis). However, topographical location also plays an important prognostic role in conjunctival melanoma. Melanomas of the limbus, as a group, tend to have a favorable prognosis, but melanomas of the fornix, palpebral conjunctiva (the inner lining of the eyelid) and caruncle are associated with an aggressive clinical course.
Question 4: Ocular cancer factoids
The overall mortality of patients with conjunctival melanoma is 25%. This tumor tends to spread first to the regional lymph nodes of the eye (parotid and submandibular nodes).
The most common malignancy of the eyelid is basal cell carcinoma. In most large eye pathology laboratories, sebaceous carcinoma is the second most common malignancy of the eyelid ... much more common than squamous cell carcinoma of the eyelid skin.
Most lymphomas presenting first in the conjunctiva or orbit are not associated with dissemination ... but it is important to classify all such lesions with the aid of immunohistochemistry, and to stage patients for evidence of extraocular disease. For unknown reasons, the rare lymphomas presenting first in the eyelid skin tend to follow an aggressive course.
The key determinant for metastasis from retinoblastoma is extraocular extension, especially through the optic nerve (the further back the optic nerve involvement, the more guarded the prognosis). Seeding of tumor into the vitreous may make it difficult for ophthalmologists to salvage vision within the eye, but this finding is not considered to be an independent risk factor for metastasis.
Question 5: Corneal transplant specimens
A busy ophthalmic practice will generate corneal tissue for the pathologist. The pathologist must be prepared to give meaningful feedback to the surgeon. If the specimen represents a second transplant in the same eye (a re-graft), was the first graft lost to an immune graft rejection or non-immunological graft failure?
The most common indications for transplant in the US include pseudophakic bullous keratopathy; Fuchs' dystrophy, and keratoconus. Macular dystrophy, an autsomal recessive condition, is rare.