Quantification of mast cells and blood vessels in the skin of patients with cutaneous mucinosis. Am J Dermatopathol. 2010;32:453-458. [PMID: 20442641 DOI: 10.1097/dad.0b013e3181b1c593]

Conjunctival Myxoid Lesions: Clinical-Pathologic Multiparametric Analysis, Including Molecular Genetics (An American Ophthalmological Society Thesis)

PURPOSE

To evaluate the clinical and pathologic characteristics of conjunctival myxoid lesions, with specific focus on PRKAR1A studies, in order to distinguish neoplastic conjunctival myxoma from other myxoid conjunctival lesions.

METHODS

A retrospective, interventional, multicenter study of all patients with conjunctival myxoma, conjunctival stromal tumor, or reactive fibromyxoid proliferation diagnosed during 1988-2018. Patient and family medical histories and clinical and pathologic characteristics of excised lesions were assessed.

RESULTS

There were 28 patients with conjunctival myxoid lesions diagnosed as myxoma (16/28), conjunctival stromal tumor (10/28), or reactive fibromyxoid proliferation (2/28). The patients with abundant myxoid matrix lesions (14/28, 50%) were younger (mean 49 [range 23-68] years) than those with scant-to-moderate myxoid matrix lesions (14/28, mean 61 [range 18-82] years; P = .04). Abundant myxoid matrix lesions more likely contained predominantly stellate cells (6/14 [43%] vs 0/14 [0%]; P = .05) and fibrillar collagen (13/14 [93%] vs 2/14 [14%]; P < .0001), conforming to the standard morphologic definition of myxoma. Absence of PRKAR1A protein expression was found in 2 lesions with morphologic features of myxoma (2/14, 14%), 1 of which demonstrated a pathogenic mutation in the PRKAR1A gene. There was no difference between the lesions with respect to other clinical and pathologic parameters.

CONCLUSIONS

PRKAR1A plays a role in the development of a subset of conjunctival myxomas, particularly in tumors fulfilling stringent morphologic criteria for myxoma. With the exception of PRKAR1A studies, current immunohistochemical panels cannot reliably distinguish between neoplastic conjunctival myxomas and other myxoid lesions, underscoring the importance of morphology in establishing accurate diagnosis.

Analogs of human genetic skin disease in domesticated animals

Genetic skin diseases encompass a vast, complex, and ever expanding field. Recognition of the features of these diseases is important to ascertain a correct diagnosis, initiate treatment, consider genetic counseling, and refer patients to specialists when the disease may impact other areas. Because genodermatoses may present with a vast array of features, it can be bewildering to memorize them. This manuscript will explain and depict some genetic skin diseases that occur in both humans and domestic animals and offer a connection and memorization aid for physicians. In addition, we will explore how animal diseases serve as a model to uncover the mechanisms of human disease. The genetic skin diseases we will review are pigmentary mosaicism, piebaldism, albinism, Griscelli syndrome, ectodermal dysplasias, Waardenburg syndrome, and mucinosis in both humans and domesticated animals.

CD34+ dermal dendritic cells and mucin deposition in dermatomyositis

Dermal mucinosis is often associated with collagen diseases such as rheumatoid arthritis, lupus erythematosus, and dermatomyositis, in addition to autoimmune thyroiditis. We report eight cases of dermal mucin deposition secondary to typical dermatomyositis with cutaneous lesions known as heliotrope rash and Gottron’s papules. Striking mucin deposition was observed in both the papillary dermis and reticular dermis of all biopsy specimens. Immunohistochemical analysis showed that CD34+ dermal dendritic cells (DDCs) in the perilesional area in combination with vimentin+ cells within the mucinous lesion might be important in giving rise to abnormal deposition of dermal mucin. On the other hand, numbers of factor XIIIa+ DDCs and tryptase+ mast cells were reduced within and surrounding the mucin deposition, as compared with those in the dermis of normal controls. A pathogenic mechanism of dermal mucin deposition is proposed.

Cutaneous mucinosis in a strain of brown-egg laying chickens

Cutaneous mucinosis is a cutaneous disorder described in humans, dogs, and rarely cats but never reported in birds. Twenty-six brown egg-laying chickens between ages 43 and 46 weeks had a history of feather loss, scaly, dry skin, weight loss, and decreased egg production. Microscopic findings in the skin included fragmentation of collagen bundles and interstitial, periadnexal, and perivascular dermal accumulation of wispy, mildly basophilic material that was also occasionally observed within the follicular epithelium. A moderate lymphoplasmacytic and heterophilic perivascular dermatitis was also observed. The wispy to granular material was diffusely Alcian blue positive and periodic acid-Schiff negative (consistent with mucin), suggesting a diagnosis of primary or secondary cutaneous mucinosis. The cause of this condition could not be determined.