Atypical temporal arteritis

Sclerosing orbital lesions: broadening the differential diagnosis of "idiopathic sclerosing pseudotumor"

Sclerosing orbital lesion
(the biopsy revealed it to be Erdheim-Chester disease)

Sclerosing lesions of the orbit can present a diagnostic conundrum. Often submitted with a differential diagnosis that includes idiopathic sclerosing pseudotumor, it is incumbent upon the pathologist to rule out other diagnostic possibilities before designating the lesion as idiopathic. In order to survey the range of diagnoses for such specimens, we searched over a 10-year period for specimens submitted to the University of Colorado pathology department which either clinically or pathologically raised the possibility of idiopathic sclerosing pseudotumor. We found 31 specimens (from 27 patients) that met criteria for review. The diagnosis for each of the 27 patients was confirmed after review of medical records. For 11 patients, a final clinicopathologic diagnosis of idiopathic sclerosing pseudotumor was rendered. The remaining diagnoses included: Wegener's granulomatosis (3), IgG4-related disease (2), reactive change to a prior procedure (2), schwannoma (2), sclerosed vascular malformation (2), Erdheim-Chester disease (1), non-Langerhans cell histiocytosis NOS (1), sarcoidosis (1), fibromyxoma (1), and thyroid eye disease (1).  Based on this institutional review, the differential diagnosis of fibrosing lesions of the orbit is broad, encompassing autoimmune, reactive, neoplastic, malformative, and endocrine disease. However, the most common final diagnosis remains idiopathic sclerosing pseudotumor.

The new WHO Ocular Tumour “Blue Book” is now available!

Prepared by 64 contributors from 22 countries

More than 400 tables and color photos 

The new edition of the WHO Classification of Tumours of the Eye is now on sale, just in time for Christmas! The latest edition is edited by Drs. Hans E. Grossniklaus, Charles Eberhart, and Tero Kivela. There are sections on all recognized neoplasms of the eye, lacrimal apparatus, and conjuctiva. Included are substantial changes to the classification of conjunctival neoplasia and melanoma, based on the latest molecular studies.  Information on clinical features in addition to prognostic and predictive factors for each tumour type are provided. Also included are updates to the existing ICD-O codes and new codes for use in epidemiology and cancer registration.

Chapters are as follows:

1. Conjunctiva and caruncle

2. Iris, ciliary body, and choroid

3. Retina and retinal pigment epithelium

4. Optic disc and optic nerve

5. Lacrimal gland

6. Lacrimal drainage system

Iridociliary melanoma invading sclera

The sclera (upper right part of picture) is being invaded by the heavily pigmented melanoma

Best Post of October 2018: Young adult with an iridic mass extending into the ciliary body

The next in our "Best of the Month" series comes from October 9, 2018:

Melanoma markers were negative. Smooth muscle markers were positive. This case was determined to be an epithelioid leiomyoma. I didn't do electron microscopy to look for mitochondia, but it may well be what Ursula Schlotzer-Schredhardt et al. have called a mitochondria-rich epithelioid leiomyoma (Arch Ophthalmol, Vol 120, January 2002).

Young adult with an iridic mass extending into the ciliary body

Melanoma markers were negative. Smooth muscle markers were positive. This case was determined to be an epithelioid leiomyoma. I didn't do electron microscopy to look for mitochondia, but it may well be what Ursula Schlotzer-Schredhardt et al. have called a mitochondria-rich epithelioid leiomyoma (Arch Ophthalmol, Vol 120, January 2002).

Salzmann nodular degeneration of the cornea

Histopathology of Salzmann nodules (*). Disruption of the Bowman membrane is demarcated in each photomicrograph by the area between the left and right arrows: (A) hematoxylin and eosin stain; (B) periodic acid-Schiff stain; (C) immunohistochemistry with antibody against pan-cytokeratin; and (D) immunohistochemistry with antibody against vimentin. (From Stone DU, et al. Histopathology of Saltzmann Nodular Corneal Degeneration. Cornea. Volume 27(2), February 2008, pp 148-151)

Salzmann nodular degeneration  was once called  Salzmann nodular dystrophy. It is now recognized that this typically unilateral disorder is not heritable and is best classifid as a secondary degenerative process of uncertain cause. Clinically, the corneal epithelium is focally elevated by white mounds of dense collagenous connective tissue. Salzmann nodular degeneration resembles a massive focal pannus histopathologically. Mounds of relatively acellular hyaline connective tissue elevate the corneal epithelium anterior to the plane of Bowman membrane, which may be destroyed.

Source: Reference: Eagle, Ralph C. Eye Pathology: An Atlas and Text [2nd edition] page 86.

A Primer on Giant Cell (Temporal) Arteritis

Neuropathologists are often tasked with handling ophthalmic pathology at their institutions. As such, they are assigned all cases submitted by ophthalmologists -- including temporal artery biopsies for determination of the presence of active giant cell (temporal) arteritis. What follows is a quick reference on the important points to remember about giant cell arteritis. (If there are things I am forgetting, please add your comments.):

Arrow points to a giant cell in a temporal artery wall
(from Robbins Basic Pathology, 10th edition)

Refering to the condition as "temporal arteritis" is not entirely accurate as giant cell arteritis is a granulomatous inflammatory disorder that can affect a variety of large and small arteries in the head. In addition to the temporal artery, ophthalmic arteries can be affected (which is the reason ophthalmologists are often the clinicians performing biopsies in suspected cases). Additionally, vertebral arteries and even the aorta (giant cell aortitis) can be involved. Since ophthalmic arteritis can lead to sudden and irreversible blindness, affected patients must be promptly diagnosed and treated. A negative biopsy result does not entirely exclude the diagnosis as the distribution of inflammation is often patchy.

Because pathologic changes tend to be patchy, examination of several cross-sectional levels is required. Involved segments exhibit nodular intimal thickening (and occasional thromboses). Most lesions exhibit granulomatous inflammation within the inner media which disrupts the internal elastic lamina. A minority of cases do not show either granulomas or giant cells, instead exhibiting only a non-specific acute and chronic inflammatory infiltrate. Healing is characterized by intimal thickening, medial thinning, and adventitial fibrosis.

Reference: Kumar V, Abbas AK, and Aster JC (eds.) Robbins Basic Pathology, Chapter 10 "Blood Vessels", 10th Edition (2018) pp. 384-5.

Best Post of January 2017: Corneal ulceration secondary to Candidal keratitis

The next in our "Best of the Month" Series is from January 20, 2017. A good photomicrograph is worth a thousand words.

GMS stain highlights fungal forms in the corneal stroma

"Gross only" sign out of intraocular lens prosthesis

When signing out our gross only IOL cases, my ophthalmologists want me to comment as to whether the "haptics" are completely present to confirm that nothing has been inadvertently left behind in the patient. If you are wondering what a "haptic" is, it the curving blue filament that emerges from the prosthetic lens serving to keep the lens in place. The term "haptic" means "related to the sense of touch"; but I am not sure why this term is used in this context. Perhaps a reader knows?

IOL with blue haptics in place

Retinal biopsy from an elderly woman with suspected ocular lymphoma

The patient had multiple foci of markedly thickened retina on exam. Ophthomologists were able to obtain a relatively large retinal biopsy. We did not find lymphoma in this case, and infections of many sorts were ruled out. But the ophthalmologists wanted an opinion as to whether retinal vasculitis was present. I wonder whether the threshold for calling vasculitis in the retina should be lower than in other tissues. Your input in the comments section would be greatly appreciated.

Low power view

Medium power showing diffuse edema

Arterioles with focus of intramural inflammatory infiltrate on right side of right vessel

Ophthalmologist and Eye Pathologist David Wilson Visits University of Colorado Pathology Department

Dr. David Wilson (left) with residents and attendings at University of Colorado Pathology Dept today

The pathology department was one stop made by Dr. David Wilson, ophthalmologist and eye pathologist from Oregon Health and Science University, when he visited the University of Colorado today.

Corneal ulceration secondary to Candidal keratitis

GMS stain highlights fungal forms in the corneal stroma

Vestige of a choroidal melanoma

Only melanin and melanophages remain in an enucleation specimen from a patient successfully treated with brachytherapy for choroidal melanoma. The eye was enucleated not because of the tumor, but because it was blind and intractably painful in the aftermath of treatment.

A case of recurrent ligneous conjunctivitis in an adult

Massive fibrin deposition in a case of recurrent ligneous conjunctivitis in an adult

I recently signed out a case of ligneous conjunctivitis, a rare form of chronic pseudomembranous conjunctivitis that is marked by a massive accumulation of fibrin. The term ligneous (from the Latin term for "woody") refers to the firm consistency of the large masses of fibrin that comprise the pseudomembranes. Ligneous conjunctivitis typically occurs in children but may recur in adults. Treatment is often challenging because the inflammation is persistent and the pseudomembranes often recur rapidly after excision. Histopathology shows two components: granulation tissue and sheets of intensely eosinophilic acellular amorphous material, which has been shown to be composed predominantly of fibrin. The mass of fibrin also incorporates other serum components such as immunoglobulin. Lesions that resemble those found in the conjunctiva can affect other mucous membranes including the larynx, vagina, and ear. Ligneous conjunctivitis is an autosomal recessive trait caused by mutations in the gene for plasminogen on chromosome 6q26.

Reference: Eagle, Ralph C. Eye Pathology: An Atlas and Text [2nd edition] page 55.

Scleral invasion by uveal melanoma

Circled cells represent superficial invasion of sclera (I don't think those cells are in a vessel)

Choroidal Involvement by Retinoblastoma

Uveal melanoma at iris root

Neoplasm is extending into and blocking anterior chamber angle

Cornea of an elderly female soft contact lens wearer afflicted by acanthamoeba keratitis

Evacuated cyst walls embedded in corneal stroma

Acathamoeba keratitis classically afflicts soft contact lens wearers who use contaminated homemade saline solutions or wear their contact lenses while swimming or in hot tubs. Corneal infection is usually very painful. In some medically intransigent cases, as exemplified in this case, corneal transplantation may be necessary. The chitinous wall of the organism is oval, while the cytoplasm typically retracts from the cyst wall in tissue sections. The cyst contains a round nucleus with a distinct nucleolus.

Acanthamoeba nucleus with distinct nucleolus

Lisch nodules in a patient with NF-1

A. Multiple tan or pale brown dome-shaped nodules on surface of iris of patient with NF-1. Lisch nodules occur in nearly all affected adults with neurofibrosis, type 1. B. Focus of partially pigmented cells rests on anterior iridic surface. Lisch nodules are melanocytic hamartomas.

From: Eagle, Ralph C. Jr.. Eye Pathology: An Atlas and Text. Second Edition (2011). Page 20.