Закономірність формування внутрішньоочних грибоподібних пухлин і гістоморфологічні патерни, що підтверджують його.

Abstract

Попереднє дослідження дозволило сформулювати закономірність утворення грибоподібних пухлин, що демонструє принципову схожість у послідовності формування сферичної частини та основи, незалежно від органу або тканини, в якій відбувається зростання. Відмінною особливістю внутрішньоочних грибоподібних пухлин є те, що пігментний епітелій сітківки, з якого вони розвиваються, не має власної стромальної території. Тому початкові стадії формування грибоподібної внутрішньоочної пухлини практично недоступні для гістоморфологічного дослідження. Були представлені гістоморфологічні особливості початкових стадій епіхоріоїдного росту меланом. Серед майже 1500 випадків внутрішньоочної меланоми, дослідженої за період з 2015 по 2025 рік, було виявлено чотири випадки, що відповідають початковому формуванню грибоподібного вузла. Ці унікальні спостереження дозволяють виявити ранні стадії розвитку внутрішньоочних меланом, демонструючи їх справжню гістогенетичну зв’язок з пігментним епітелієм сітківки.

Introduction. It should be noted that mushroom-shaped tumor growth is common in oncology. Samples of such tumors can be found in the skin, mucous membranes of the respiratory and gastrointestinal tracts, serous membranes and endometrium.. Despite differences in size, histological structure, and grade of malignancy, they all share a common design: a spherical nodule rising above the surface of the organ to which it is connected and from whose cells it arises. As emphasized in previous studies, ophthalmic oncology has developed its own understanding of mushroom tumor growth over many decades. Analysis of mushroom tumor growth in various locations revealed fundamental discrepancies between the accepted explanation for mushroom tumor growth in ophthalmic oncology and the actual mechanism of formation of mushroom tumors outside the eyeball. A theoretical study has allowed us to formulate a pattern for the formation of intraocular mushroom tumors, demonstrating a fundamental similarity in the sequences of formation of the spherical portion and base of these tumors, regardless of the organ or tissue where the growth occurs. Atthesame time, adistinctivefeatureofintraocularmushroom tumors is that the retinal pigment epithelium, from which they develop, unlike other epithelia that can also be the source of mushroom tumors, lacks its own stromal territory. Therefore, the formation of an epichoroidal tumor nodule becomes possible only after the neoplasm penetrates the choroid. For this reason, the initial stages of the formation of a mushroom-shaped intraocular tumor are practically inaccessible for histomorphological examination, given also the fact that small tumors, as a rule, become objects of organ-preserving treatment. Aim. The aim of this work is to present the histomorphological features of the initial stages of epichoroidal growth of melanomas based on the discovered model of hTCurrent and archival data covering approximately 1,500 intraocular melanomas from 2015 to 2025 were analyzed. Four cases were identified that met the criteria outlined above. For each case, 20 to 46 serial histological sections stained with hematoxylin and eosin were obtained and analyzed, allowing for an assessment of all areas of the epichoroidal nodule, particularly in its relationship with the choroid. Results. For many decades, mushroom tumor growth in the eye was attributed to a rupture of Bruch’s membrane by a tumor growing in the choroid. Therefore, rare, isolated observations of epichoroidal growth without a tumor nodule in the choroid could not be correctly interpreted. Thus, individual observations were associated with tumor processes in the pigment epithelium based on the fact that they were not penetrated into the choroid. Our observations show that epichoroidal tumor growth is impossible without disruption of Bruch’s membrane, which creates the conditions for vascular penetration and stromal formation, without which a tumor nodule cannot form. Thus, in all four cases of epichoroidal growth studied, a Bruch’s membrane defect was present, although its detection sometimes required the examination of a large number of histological sections. In some sections, the tumor nodule appeared isolated from the choroid by preserved Bruch’s membrane. However, inflammatory (lymphocytic) infiltration of the choroid in the projection of the epichoroidal tumor growth was always detected. In two of the four cases, the epichoroidal nodule had the usual histologic features of «uveal» melanoma: in one case, the nodule was nonpigmented, predominantly epithelioid type, and in the other case it corresponded to pigmented melanoma of mixed type. In one case, the epichoroidal growth consisted primarily of intensely pigmented epithelioid cells, forming patterns characteristic of hyperplastic pigment epithelium. However, the size of the tumor nodule, its prominence, and its relationship with the adjacent choroid indicated true neoplasia. A fairly extensive defect in Bruch’s membrane indicated the aggressive nature of the tumor. The fourth case studied is of particular interest. Tumor proliferation of spindle-shaped, nonpigmented cells was detected exclusively in the area between Bruch’s membrane and the photoreceptor layer of the retina, which did not clearly adhere to the tumor nodule. This tumor, unlike all the previous ones, did not have clearly defined melanoma patterns. However, discomplexation of the pigment epithelium and destruction of Bruch’s membrane in the projection of the tumor growth indicate its aggressive and obvious neoplastic nature. It is important to emphasize that all tumors had macroscopic characteristics typical of intraocular melanomas. In two cases, the tumors were detected ophthalmoscopically near the optic disc. Despite the small size of the nodules and their prominence of 3-4 mm, enucleation was performed due to the lack of promise of organ-preserving treatment. In two cases, the tumors were discovered by chance during ultrasound examination of eyes not accessible to ophthalmoscopy. Conclusions. The previously discovered pattern of intraocular mushroom-shaped tumor formation allows for a new look at rare cases of epichoroidal growth, previously sporadically described as unusual intraocular tumors. Our study of four cases of epichoroidal growth, identified among 1,500 intraocular melanomas, confirms the extreme rarity of these variants. These observations make it possible to identify the earliest stages of the development of intraocular melanomas, demonstrating their true histogenetic connection with the retinal pigment epithelium.