*4.1.2 Primary acquired melanosis (PAM)*

Primary acquired melanosis, a frequent benign conjunctival pigmented lesion, can evolve into conjunctival melanoma. It is usually observed in middle-aged or elderly patients and, in contrast with conjunctival nevus, it is patchy, flat, and noncystic and it is usually not well circumscribed. This lesion may arise with or without atypia, and the presence of the atypia leads to a 50% chance of melanoma [25].

## *4.1.2.1 OCT appearance*

*A Practical Guide to Clinical Application of OCT in Ophthalmology*

effect of the needling on the bleb ASOCT appearance.

**4. The use of oct in Conjunctival pathologies**

follow up after the surgical excision of the tumor.

cytes in the stroma near the basal layers of the epithelium.

**4.1 Conjunctival tumors**

genital and acquired lesions.

tival tumors.

or metastatic.

and lymphoma.

growth is documented.

*4.1.1.1 OCT appearance*

tive value is 60% [22].

rule out malignancy.)

and not heavily pigmented.

ally confirms a chronic pathology) [21].

*4.1.1 Nevus*

fluid-filled cavity area [13]. The study by Guthoff et al. [17], instead, analyzes the

One of the most studied and validated applications of ASOCT regards conjunc-

Many reports [18–24] demonstrate that the OCT study of conjunctival tumors can help the clinician to: make the diagnosis, help to distinguish among different types of neoplasm or between benign and malign neoplasms, help to assess the

The classification of the conjunctival tumors may be summarised in the con-

The acquired lesions can be distinguished in: pigmented and non-pigmented

Nevus is the most common melanocytic tumor of the conjunctiva. It shows up as a discrete variably pigmented, slightly elevated sessile which usually remains quite stable during life with <1% risk of transformation into malignant melanoma. Histopathologically, a conjunctival nevus is composed of nests of benign melano-

A periodical follow-up, together with photographic comparison, is the best way to verify whether it is growing: sometimes you may need the mass excision if any

The study of Shields et al. on 22 conjunctival nevi demonstrated that all margins of conjunctival nevi can be observed through ASOCT (high resolution in 100% of anterior borders and 82% of posterior borders). The sensitivity of AS-OCT for the detection of intrinsic cysts in a conjunctival nevus is 80%, its specificity is 100%, its positive predictive value is 100%, and its negative predic-

Regarding conjunctival nevi we can conclude that ASOCT seems to be more accurate in assessing the extent of these tumors as long as the nevus is not very thick

AS-OCT can also be used for differentiating a nevus from melanoma: unlike melanomas, the nevi usually contain intralesional cystic space (their presence usu-

(Note that it is still debated whether the presence of cysts does not definitively

or, depending on the origin of the mass, in surface-epithelial, melanocytic, fibrous-vascular, myogenic, neural, lipomatous, lymphoid, histiocytic, leukemic

Essentially the most studied conjunctival lesions are the pigmentedmelanocytic. This family of lesions includes nevus, racial melanosis, PAM (primary acquired melanosis) and melanoma. Among the non-melanocytic neoplastic lesions, the most frequently studied are squamous cell carcinoma

**52**

Histopathologically, PAM is characterized by the presence of abnormal melanocytes near the basal layer of the epithelium so the PAM ASOCT images is characterized by normal thickness but moderately hyperreflective basal epithelium with no invasion of the subepithelial space [21].
