Ambiguity around the histopathology diagnosis!!!
Histopathology is considered as a gold standard for diagnosis. It gives a direct insight on exact cellular and molecular phenomenon and as we all know “cells don’t lie”….
However, if the question is asked that whether histopathology answers all the problems accurately? The answer is “may be not”…
There are some entities which carry their own spectrums, their own questions and their own controversies. This particularly, is not in best interest of the histopathologists. Giving diagnosis is just not about identifying the pathology, but also understanding the pathology to the core and to give the surgeon the basic idea about the general prediction of the behavior and thereby the prognosis of that particular pathology.
Hence, the roadmap of the disease should be clear to establish the authentic diagnosis. However, there are certain pathologies in oral pathology which does not have their roots of existence clear. Controversies and differing opinions regarding their genesis, independent existence and thereby their future prognosis…
As an oral pathology practitioner, I feel the first step towards proper management of such cases with controversial nature, is documentation…
Today’s editorial is directed towards reporting one such controversial case of Unicystic Ameloblastoma arising from the lining of dentigerous cyst (DC).
The concept of Ameloblastoma arising from the lining of dentigerous cyst has long been under discussion with multiple schools of thoughts published regarding its evolution and behavior.1 Let us have an update regarding the same.
It has long been postulated that the epithelial lining of the cysts are having potential to transform into benign or malignant tumors and the epithelial lining of DC is not an exception to that.2 Although challenged by the “horses” himself that is Shear that the occurrence of the tumor from the cystic lining is just an over exaggeration of the simple stage of tumerogenesis.3 It has been evaluated and confirmed on the molecular level too that cyst linings have the potential of tumor formation. There has been increase in the expression of proliferative markers including Ki-67, p63, CD -10, osteopontin, etc in the cystic lining which shows ameloblastomatous transformation. Other studies have also reported loss of heterozygosity (LOH) and mutation in PTCH genes in odontogenic keratocyst as well as DC. Researchers thereby have also laid down conclusions that lining of DC is made up of single lineage of monoclonal cells that possess a neoplastic genotype.2, 4 Thereby, tumors including ameloblastomas are known to arise from the cyst lining due to disruption in regular cell cycle and imbalance between oncogenes and tumor suppressor genes leading to hyperproliferation of the lining cells.2
The early ameloblastomatous changes as put forward by Vicker and Gorlin (VG)5 include-
Epithelial lining cells comprising of columnar cells
Nuclear hyperchromatism
Palisading and polarization of nucleus
Cytoplasmic vacuolization
Intercellular spacing
Subepithelial hyalinization
Presence of stellate reticulum
These characteristics helps the pathologists identify the ameloblastomas on their most early phases also sometimes referred to as “Unicystic Ameloblastoma” (Figure 1).
Figure 1
10X view of the H & E section showing Dentigerous Cyst lining proliferating into unicystic ameloblastoma with basal palisading & stellate reticulum like cells
The case in the present editorial reports a similar case where such picture of ameloblastomatous transformation along the lining of DC was observed. The findings are similar with the case published in the year 2017 where the occurrence of the tumorous changes away from the cystic lining of DC, features of VG criteria and presence of unerupted tooth in the proximity confirms the occurrence of an ameloblastoma arising from the lining of DC.2 (Figure 2)
The silver lining to the dark cloud though is amongst all this controversy of whether there is transformation of cyst lining or unicystic ameloblastoma is an independent entity, the biologic behavior is not aggressive as conventional ameloblastomas and thereby conservative treatment with carnoy’s solution and follow up is the protocol for such cases. However, knowledge regarding these ambiguous entities warrants attention especially for histopathologists for longterm evaluation of such lesions.
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