Management of primary acquired melanosis (PAM) of the eye (State of Research Paper)

With regard to acquired melanosis of the conjunctiva, there is still neither a worldwide uniform nomenclature nor reliable data on how frequent this type of pigment disorder is. This is even more true for the estimation of the risk of progression into cancer as well as the clinical management of this entity. This short paper presents the current, partly contradictory scientific knowledge which is available.

Histopathological Variability and Concomitant Lesions in Pterygium in a Large Case Series

Pterygium is a common lesion consisting of fleshy conjunctival growth extending towards the cornea. There is no documented risk of malignant transformation; however, concomitant disease is not rare, and its link to sunlight exposure indicates a risk of other malignancies. The purpose of our study is to describe histopathological features of resected pterygiums and to recognize patients at risk of other conjunctival diseases. One hundred and forty-nine formalin-fixed and paraffin-embedded pterygium samples were subjected to histopathological analysis. Histological H&E sections were obtained and digitalized using a Zeiss Axio Scan.Z1 slide scanner. Thirteen predefined morphological features were used to record histopathological changes in the epithelium and substantia propria. Neovascularization was observed in 54% of the samples. Sun damage, comprising solar elastosis and stromal plaque, was present in 81% of the samples. Variation in epithelial thickness was the most common change, with acanthosis and atrophy being observed in 62% and 26% of the samples, respectively. In our series, 21% (31/149) of pterygiums showed mild to moderate dysplasia, a finding that may be associated to ocular surface squamous neoplasia (OSSN). Moreover, 32% (47/149) of the cases showed melanocytic hyperplasia, which could represent primary acquired melanosis (PAM). There is a positive correlation between dysplasia and chronic inflammation p = 0.012 and an inverse correlation with epithelial atrophy p = 0.001 and neovascularization p = 0.05 . Similarly, a positive correlation is observed between goblet cell hyperplasia and melanocytic hyperplasia p = 0.02 . Our findings show that pterygiums harbour histological features that may be suggestive of OSSN or PAM in 53% of our patients. Whilst being on the benign side of the spectrum, these two entities are known for their potential progression to malignancy. A recommendation is made for all surgically excised pterygiums to be sent for histopathological diagnosis, and clear guidelines for reporting of these lesions should be established. Associated histopathological findings suggestive of other concomitant diseases should be identified to insure adequate follow-up of these patients.

Clinical and Histopathological Features of Corneal Primary Acquired Melanosis and Melanoma

<b><i>Aim:</i></b> The aim of this study is to describe the clinical and pathologic features of corneal primary acquired melanosis (PAM) and melanoma. <b><i>Methods:</i></b> We describe 3 cases in total: two cases of corneal melanomas and 1 case of corneal PAM. The eyes were processed routinely for histopathological examination. Clinical histories, treatments, and outcomes were reviewed. <b><i>Results:</i></b> Corneal melanomas arose from recurrence of conjunctival melanoma or conjunctival PAM at the limbus. One patient had a recurrence after excision of a limbal melanoma, another had a de novo corneal melanoma, and the last patient had corneal PAM in the setting of conjunctival PAM with atypia. All lesions were excised with adjuvant alcohol debridement and cryotherapy with no recurrence ranging from 1 week to 8 years. <b><i>Conclusions:</i></b> Corneal melanomas arise at the limbus from corneal PAM or conjunctival atypia. They can appear after excisional removal of a conjunctival melanoma. Surgical excision with alcohol debridement and adjuvant cryotherapy is successful.

Primary acquired melanosis/melanoma: utility of conjunctival map biopsy

AimTo assess the role of map biopsy in patients with conjunctival primary acquired melanosis (PAM)/melanoma.MethodsRetrospective case series of 400 conjunctival biopsy samples of 51 unique patients in a tertiary referral centre.ResultsEach patient underwent one diagnostic biopsy and several additional map biopsies (range 2–7) providing a total of 400 samples for the analysis (55 diagnostic biopsies, 345 map biopsies). The median age was 63 years old (range 20–88) with women representing 67% of the cases. Histopathological findings were graded as negative for melanosis/normal (grade 0), melanosis without atypia (grade 1), melanosis with mild atypia (grade 2), melanosis with severe atypia (grade 3) or invasive melanoma (grade 4). Clinicopathologic concordance was observed in the majority of the map biopsies (313, 91%) (positive: clinical+/path+ (57,17%), negative: clinical−/path− (256, 74%)). Three discordant samples (clinical−/path+) represented PAM sine pigmento. The histopathological spectrum of atypia was absent (40, 73%) or limited (11, 20%) in the majority of cases with tendency to cluster as low-grade or high-grade atypia. Map biopsy led to the identification of six patients (11%) with severe atypia, requiring topical mitomycin (MMC). Similarly, in 29 cases, periodic observation without topical MMC was recommended. One case of invasive melanoma transformation occurred in the MMC-treated group.ConclusionsMap biopsy enhances overall assessment of the anatomic and pathologic extent, impacting use of adjuvant topical chemotherapy. In absence of map biopsy, it would be impossible to diagnose PAM sine pigmento. Additional corroborative work is needed to validate our observations.

Primary acquired melanosis (PAM) without atypia/WHO low-grade conjunctival melanocytic intraepithelial lesion over areas of oculodermal melanocytosis

An elderly white man with a history of left oculodermal melanocytosis presented with new onset brown pigmentation of the left bulbar and inferior tarsal conjunctiva. The bulbar conjunctival pigmentation was at the level of the conjunctival epithelium and was overlying areas of typical slate-grey scleral pigmentation characteristic of oculodermal melanocytosis. Both areas of new pigmentation were biopsied. The bulbar conjunctiva revealed primary acquired melanosis (PAM) without atypia with increased melanin production and the tarsal conjunctival biopsy showed PAM without atypia sine pigmentio overlying areas of substantia propria spindle-shaped heavily pigmented melanocytes of oculodermal melanocytosis. The case report examines the relationship between the epithelial and substantia propria melanocytes and correlates the findings with what is known about this association from the dermatopathology literature.