Urea- and Thiourea-Based Receptors for Anion Binding.

ConspectusOver the past five decades, significant progress has been made in the field of anion recognition with a diverse variety of synthetic receptors because of the fundamental importance of anions in chemical, environmental, and biological processes. In particular, urea- and thiourea-based molecules offering directional binding sites are attractive receptors for anions due to their ability to bind anions employing primarily hydrogen-bonding interactions under neutral conditions and have gained a recent paramount attention in the area of supramolecular chemistry. The presence of two imine (-NH) groups on each urea/thiourea functionality in these receptors gives them potential for excellent binding of an anion, mimicking the natural binding process in living cells. The increased acidity offered by thiocarbonyl groups (C═S) in a thiourea-functionalized receptor could enhance its anion binding ability as compared to its analogous urea-based receptor containing a carbonyl (C═O) group. During the last several years, our group has been involved in exploring a wide variety of synthetic receptors, and we have studied them with anions experimentally and computationally. In this Account, we will highlight the overall summary of our group's efforts focusing on anion coordination chemistry of urea- and thiourea-based receptors with varying linkers (rigid and flexible), dimensions (dipodal and tripodal), and functionalities (bifunctional, trifunctional, and hexafunctional). Depending on the linkers and attached groups, bifunctional-based dipodal receptors can bind anions forming 1:1 or 1:2 complexes. A dipodal receptor with flexible aliphatic or rigid m-xylyl linkers forms a cleft to bind a single anionic species in the pocket. However, a dipodal receptor with p-xylyl linkers binds anions in both 1:1 and 1:2 binding modes. As compared to a dipodal receptor, a tripodal receptor provides a more organized cavity for an anion, forming predominantly a 1:1 complex, while the binding strength and selectivity are influenced by linking chains and terminal groups. A hexafunctional-based tripodal receptor bridged with o-phenylene groups provides two clefts that can host two small anions or one large anion. However, a hexafunctional receptor with p-phenylene groups as linkers binds two anions, one at an inner pocket and the other at an outer pocket. It was shown that the presence of suitable chromophores at the terminal groups makes the receptor useful for the naked-eye detection for certain anions (e.g., fluoride, acetate) in solution. The field of anion binding chemistry is rapidly growing, and this Account aims to provide fundamental aspects influencing the binding strength and selectivity of anionic species with abiotic receptors which might eventually be useful for the development of new devices for binding, sensing, and separating biologically and environmentally important anions.

Dinuclear Iron(III) and Cobalt(III) Complexes Featuring a Biradical Bridge: Their Molecular Structures and Magnetic, Spectroscopic, and Redox Properties.

Bis-bidentate ligand H4LB featuring two o-amidophenol noninnocent units was used to synthesize novel binuclear complexes [(LR)MIII(•LB•)MIII(LR)](ClO4)2, M = Fe (1) and Co (2, 3), with HLR (R = CH3, Cl) being the facially coordinating tetradentate coligands. Upon the synthesis, the fully reduced amidophenolate form of the ligand (LB)4- becomes oxidized, resulting in the formation of a rare example of a biradical (•LB•)2- bridge connecting two metal ions, as supported by X-ray crystallography. The electronic structures of the complexes have been probed by Mössbauer spectroscopy, magnetic susceptibility measurements, and electron paramagnetic resonance (EPR) spectroscopy. Species 1 contains two high-spin Fe(III) ions (S = 5/2) each coupled strongly antiferromagnetically (|J| > 150 cm-1; H = -2JS1S2) with a semiquinone π-radical (S = 1/2) form of the bridging (•LB•)2- ligand. The effective S = 2 spins of each [Fe(III)+R●] monomeric unit are then weakly ferromagnetically coupled with J = +0.22 cm-1. Species 2 and 3 reveal very similar electronic structures: the low-spin Co(III) ion is diamagnetic, which leaves the two-spin carriers at the bridging (•LB•)2- biradical to display an isotropic EPR signal at g = 1.995 for 2 (1.993 for 3) in solution at room temperature and in the frozen state with no hyperfine structure. The weak half-field signal at g = 3.988 for 2 (3.978 for 3) was also observed at 17 K for the spin-forbidden |ΔMS| = 2 transition due to ferromagnetically coupled S = 1/2 spins (J = +47 cm-1) of the bridging biradical. The compounds show rich electrochemistry, displaying two (1) or four (2, 3) one-electron reversible processes. Normal and differential pulse voltammetry as well as constant potential coulometry, combined with EPR experiments, confirmed that the observed electron transfers are all localized at the bridging noninnocent (•LB•)2- ligand.

Ligand-Induced Tuning of the Oxidase Activity of µ-Hydroxidodimanganese(III) Complexes Using 3,5-Di-tert-butylcatechol as the Substrate: Isolation and Characterization of Products Involving an Oxidized Dioxolene Moiety.

Oxidase activities of a µ-hydroxidodimanganese(III) system involving a series of tetradentate capping ligands H2LR1,R2 with a pair of phenolate arms have been investigated in the presence of 3,5-di-tert-butylcatechol (H2DBC) as a coligand cum-reductant. The reaction follows two distinctly different paths, decided by the substituent combinations (R1 and R2) present in the capping ligand. With the ligands H2Lt-Bu,t-Bu and H2Lt-Bu,OMe, the products obtained are semiquinonato compounds [MnIII(Lt-Bu,t-Bu)(DBSQ)]·2CH3OH (1) and [MnIII(Lt-Bu,OMe)(DBSQ)]·CH3OH (2), respectively. In the process, molecular oxygen is reduced by two electrons to generate H2O2 in the solution, as confirmed by iodometric detection. With the rest of the ligands, viz., H2LMe,Me, H2Lt-Bu,Me, H2LMe,t-Bu, and H2LCl,Cl, the products initially obtained are believed to be highly reactive quinonato compounds [MnIII(LR1,R2)(DBQ)]+, which undergo a domino reaction with the solvent methanol to generate products of composition [MnIII(LR1,R2)(BMOD)] (3-6) involving a nonplanar dioxolene moiety, viz., 3,5-di-tert-butyl-3-methoxy-6-oxocyclohexa-1,4-dienolate (BMOD-). This novel dioxolene derivative is formed by a Michael-type nucleophilic 1,4-addition reaction of the methoxy group to the coordinated quinone in [MnIII(LR1,R2)(DBQ)]+. During this reaction, molecular oxygen is reduced by four electrons to generate water. The products have been characterized by single-crystal X-ray diffraction analysis as well as by spectroscopic methods and magnetic measurements. Density functional theory calculations have been made to address the observed influence of the secondary coordination sphere in tuning the two-electron versus four-electron reduction of dioxygen. The semiquinone form of the dioxolene moiety is stabilized in compounds 1 and 2 because of extended electron delocalization via participation of the appropriate metal orbital(s).

Pentanuclear 3d-4f Heterometal Complexes of M(II)3Ln(III)2 (M = Ni, Cu, Zn and Ln = Nd, Gd, Tb) Combinations: Syntheses, Structures, Magnetism, and Photoluminescence Properties.

A new family of pentanuclear 3d-4f heterometal complexes of general composition [Ln(III)2(M(II)L)3(µ3-O)3H](ClO4)·xH2O (1-5) [Ln = Nd, M = Zn, 1; Nd, Ni, 2; Nd, Cu, 3; Gd, Cu, 4; Tb, Cu, 5] have been synthesized in moderate yields (50-60%) following a self-assembly reaction involving the hexadentate phenol-based ligand, viz., N,N-bis(2-hydroxy-3-methoxy-5-methylbenzyl)-N('),N(')-diethylethylenediamine (H2L). Single-crystal X-ray diffraction analyses have been used to characterize these complexes. The compounds are all isostructural, having a 3-fold axis of symmetry that passes through the 4f metal centers. The [M(II)L] units in these complexes are acting as bis-bidentate metalloligands and, together with µ3-oxido bridging ligands, complete the slightly distorted monocapped square antiprismatic nine-coordination environment around the 4f metal centers. The cationic complexes also contain a H(+) ion that occupies the central position at the 3-fold axis. Magnetic properties of the copper(II) complexes (3-5) show a changeover from antiferromagnetic in 3 to ferromagnetic 3d-4f interactions in 4 and 5. For the isotropic Cu(II)-Gd(III) compound 4, the simulation of magnetic data provides very weak Cu-Gd (J1 = 0.57 cm(-1)) and Gd-Gd exchange constants (J2 = 0.14 cm(-1)). Compound 4 is the only member of this triad, showing a tail of an out-of-phase signal in the ac susceptibility measurement. A large-spin ground state (S = 17/2) and a negative value of D (-0.12 cm(-1)) result in a very small barrier (8 cm(-1)) for this compound. Among the three Nd(III)2M(II)3 (M = Zn(II), Ni(II), and Cu(II)) complexes, only the Zn(II) analogue (1) displays an NIR luminescence due to the (4)F(3/2) → (4)I(11/2) transition in Nd(III) when excited at 290 nm. The rest of the compounds do not show such Nd(III)/Tb(III)-based emission. The paramagnetic Cu(II) and Ni(II) ions quench the fluorescence in 2-5 and thereby lower the population of the triplet state.

Nonoxido Vanadium(IV) Compounds Involving Dithiocarbazate-Based Tridentate ONS Ligands: Synthesis, Electronic and Molecular Structure, Spectroscopic and Redox Properties.

A new series of nonoxido vanadium(IV) compounds [VL2] (L = L(1)-L(3)) (1-3) have been synthesized using dithiocarbazate-based tridentate Schiff-base ligands H2L(1)-H2L(3), containing an appended phenol ring with a tert-butyl substitution at the 2-position. The compounds are characterized by X-ray diffraction analysis (1, 3), IR, UV-vis, EPR spectroscopy, and electrochemical methods. These are nonoxido V(IV) complexes that reveal a rare distorted trigonal prismatic arrangement around the "bare" vanadium centers. Concerning the ligand isomerism, the structure of 1 and 3 can be described as intermediate between mer and sym-fac isomers. DFT methods were used to predict the geometry, g and (51)V A tensors, electronic structure, and electronic absorption spectrum of compounds 1-3. Hyperfine coupling constants measured in the EPR spectra can be reproduced satisfactorily at the level of theory PBE0/VTZ, whereas the wavelength and intensity of the absorptions in the UV-vis spectra at the level CAM-B3LYP/gen, where "gen" is a general basis set obtained using 6-31+g(d) for S and 6-31g for all the other elements. The results suggest that the electronic structure of 1-3 can be described in terms of a mixing among V-dxy, V-dxz, and V-dyz orbitals in the singly occupied molecular orbital (SOMO), which causes a significant lowering of the absolute value of the (51)V hyperfine coupling constant along the x-axis. The cyclic voltammograms of these compounds in dichloroethane solution display three one-electron processes, two in the cathodic and one in the anodic potential range. Process A (E1/2 = +1.06 V) is due to the quasi-reversible V(IV/V) oxidation while process B at E1/2 = -0.085 V is due to the quasi-reversible V(IV/III) reduction, and the third one (process C) at a more negative potential E1/2 = -1.66 V is due to a ligand centered reduction, all potentials being measured vs Ag/AgCl reference.

Metastatic mucinous adenocarcinoma from breast mimicking a pyogenic granuloma in the gingiva: a case report.

Mucin-producing adenocarcinomas (MAC) are an extremely rare, indistinct group of neoplasm having either a salivary gland origin or with prominent glandular component. The diagnosis is chiefly based on the histological aspect conjoined with immunohistochemical evaluation as clinico-radiographical features are non-specific. It can arise as a primary metastasis to soft tissues, most commonly from either lung, breast, kidney, or colon. This paper reports a 51-year-old woman with buccolingual gingival swelling having a final diagnosis of metastatic mucinous adenocarcinoma from the breast. A tissue biopsy was performed followed by immunohistochemistry that confirmed the diagnosis. They are extremely rare, making the diagnosis challenging as it may mimic a benign neoplasm. It accounts for approximately 1% of all oral malignant neoplasms having gingival propensity. The clinician should therefore take into account every diagnostic aspect while encountering such oral lesions to achieve proper patient welfare.

Fibroblastic osteosarcoma: A perplexing entity.

Osteosarcoma (OS), also referred to as osteogenic sarcoma, is the most common primary malignant tumour affecting long bones, characterised by the proliferation of osteoblastic precursor cells and the production of osteoid or immature bone. OSs of the head and neck region have unique biology, exhibiting a clinical behaviour and a natural history that are distinct from OSs of the trunk and extremities. Similarly, their radiological appearance and histological growth pattern can be quite diverse proving to be a challenge to histopathologists to arrive at a diagnosis. Hence, OSs of the jaw remain enigmatic, and a number of difficulties related to their diagnosis and treatment are yet to be resolved. This article reports on a case of advanced OS of the mandible in a 45-year-old woman who came for the evaluation of swelling. This case illustrates the various modalities of diagnosis, such as radiology, histopathology and immunohistochemistry for the confirmation of the variants of OS, leading to an enormously improved quality of life by offering an improved opportunity for cure and treatment.

Multi-Color-Emissive Magneto-Luminescent Nanoarchitectures for Targeted Identification of Heterogeneous Exosomes Associated with Lung Cancer Metastasis.

Due to the lack of early detection before metastasis and failure of current therapy to cure the disease, lung cancer contributes to the highest cancer-related mortality worldwide. Tenascin C (TNC) (+) exosomes promote metastasis, amphiregulin (AREG) (+) exosomes are associated with chemotherapy resistance, and programmed cell death ligand-1 (PDL-1) (+) exosomes are associated with immunotherapy resistance, and they are emerging as biomarkers in clinics. However, due to heterogeneity, rapid isolation and multiplex detection of these exosomes are challenging. Herein, we report the design of an antibody-conjugated multi-color (orange, yellow, and green)-emissive carbon dot (CD)-attached cobalt spinel ferrite (CoFe2O4)-based magneto-luminescent nanoarchitecture for targeted capturing and identification of TNC (+), AREG (+), and PDL-1(+) exosomes selectively and simultaneously from whole blood samples. More importantly, to capture and identify the targeted AREG (+) exosome from an infected whole-blood sample, an anti-AREG antibody-attached green (520 nm)-emissive CD-conjugated CoFe2O4 nanoparticle-based magnetic-green luminescence nanoarchitecture was developed. Similarly, an anti-PDL-1 antibody-attached orange (600 nm)-emissive CDs-based magnetic-orange luminescence nanoarchitecture has been produced to capture and identify the PDL-1 (+) exosome. Furthermore, an anti-TNC antibody-attached yellow (560 nm)-emissive CD-based magnetic-orange luminescent nanoarchitecture has been designed to capture and identify the TNC (+) exosome. Notably, our finding reveals that 100% TNC (+) exosomes can be captured and imaged selectively from an infected blood sample using an anti-TNC antibody-conjugated nanoarchitecture. In addition, 100% AREG (+) exosomes can be captured and imaged selectively using an anti-AREG antibody-conjugated nanoarchitecture. Moreover, 100% PDL-1 (+) exosomes can be captured and imaged selectively using an anti-PDL-1 antibody-conjugated nanoarchitecture. Furthermore, we have demonstrated that a multi-color-emissive nanoarchitecture can be used for capturing and imaging all three exosomes simultaneously.

2D Fluorinated Graphene Oxide (FGO)-Polyethyleneimine (PEI) Based 3D Porous Nanoplatform for Effective Removal of Forever Toxic Chemicals, Pharmaceutical Toxins, and Waterborne Pathogens from Environmental Water Samples.

Although water is essential for life, as per the United Nations, around 2 billion people in this world lack access to safely managed drinking water services at home. Herein we report the development of a two-dimensional (2D) fluorinated graphene oxide (FGO) and polyethylenimine (PEI) based three-dimensional (3D) porous nanoplatform for the effective removal of polyfluoroalkyl substances (PFAS), pharmaceutical toxins, and waterborne pathogens from contaminated water. Experimental data show that the FGO-PEI based nanoplatform has an estimated adsorption capacity (qm) of ∼219 mg g-1 for perfluorononanoic acid (PFNA) and can be used for 99% removal of several short- and long-chain PFAS. A comparative PFNA capturing study using different types of nanoplatforms indicates that the qm value is in the order FGO-PEI > FGO > GO-PEI, which indicates that fluorophilic, electrostatic, and hydrophobic interactions play important roles for the removal of PFAS. Reported data show that the FGO-PEI based nanoplatform has a capability for 100% removal of moxifloxacin antibiotics with an estimated qm of ∼299 mg g-1. Furthermore, because the pore size of the nanoplatform is much smaller than the size of pathogens, it has a capability for 100% removal of Salmonella and Escherichia coli from water. Moreover, reported data show around 96% removal of PFAS, pharmaceutical toxins, and pathogens simultaneously from spiked river, lake, and tap water samples using the nanoplatform.

Triple-stranded helicates of zinc(II) and cadmium(II) involving a new redox-active multiring nitrogenous heterocyclic ligand: synthesis, structure, and electrochemical and photophysical properties.

The protonated form [H(2)(L)](CF(3)SO(3))(2) (1) of a new redox-active bis-bidentate nitrogenous heterocyclic ligand, viz., 3,3'-dipyridin-2-yl[1,1']bi[imidazo[1,5-a]pyridinyl] (L), and its zinc(II) and cadmium(II) complexes (2 and 3) have been synthesized and characterized by single-crystal X-ray diffraction analysis. In the solid state, both 2 and 3 have triple-stranded helical structures involving ligands that experience twisting and bending to the extent needed by the stereoelectronic demand of the central metal ion. The metal centers in the zinc(II) complex [Zn(2)(L)(3)](ClO(4))(4) (2) are equivalent, each having a distorted octahedral geometry, flattened along the C(3) axis with a Zn1···Zn1# separation of 4.8655(13) Å. The cadmium complex [Cd(2)(L)(3)(H(2)O)](ClO(4))(4) (3), on the other hand, has a rare type of helical structure, showing coordination asymmetry around the metal centers with a drastically reduced Cd1···Cd2 separation of 4.070 Å. The coordination environment around Cd1 is a distorted pentagonal bipyramid involving a N(6)O donor set with the oxygen atom coming from a coordinated water, leaving the remaining metal center Cd2 with a distorted octahedral geometry. The structures of 2 and 3 also involve anion-π- and CH-π-type noncovalent interactions that play dominant roles in shaping the extended structures of these molecules in the solid state. In solution, these compounds exhibit strong fluxional behavior, making the individual ligand strands indistinguishable from one another, as revealed from their (1)H NMR spectra, which also provide indications about these molecules retaining their helical structures in solution. Electrochemically, these compounds are quite interesting, undergoing ligand-based oxidations in two successive one-electron steps at E(1/2) of ca. 0.65 and 0.90 V versus a Ag/AgCl (3 M NaCl) reference. These molecules are all efficient emitters in the red and blue regions because of ligand-based π*-π fluorescent emissions, tuned appropriately by the attached Lewis acid centers.

Gnathic variant of primary adenoid cystic carcinoma: A unique case report.

Adenoid Cystic Carcinoma (AdCC) is an uncommon malignant epithelial salivary gland neoplasm, which is indolent yet persistent. Intraosseous /central variant of AdCC of the jaw is poorly understood owing to its innocuous clinical presentation thus posing a diagnostic challenge. AdCC is characterized by perineural invasion, late distant metastasis and a high recurrence rate , thus having a major effect on the mortality and morbidity rate. It is often diagnosed at an advanced stage which is chiefly achieved through histological examination and complete clinic-radiological work up. A clinical case of an intraosseous variant of AdCC, involving the mandible of a 49 year old male patient is discussed herewith, encompassing the entire spectrum of clinicopathological, radiological and treatment modalities rendered.

Primary amelanotic malignant melanoma of parotid and submandibular salivary gland: A rare case report.

Primary amelanotic malignant melanomas (AMMs) of the parotid and submandibular salivary glands are extremely rare with only a few reported cases due to its low incidence and misdiagnosis. Malignant melanoma (MM) has a high predilection for the head-and-neck region and majority of the cases in the parotid gland reported as association with metastasis in and around the gland from a cutaneous primary tumor. Immunohistochemistry is solely needed for confirmation of diagnosis and MMs give positive reactivity for melan-A, HMB-45, and S-100. Prognosis for AMM in the mucosal or salivary gland regions is much poorer than cutaneous regions because of anatomic considerations and its delayed diagnosis. The treatment of choice is radical surgery and parotidectomy along with radiotherapy and chemotherapy.

Atypical Presentation of Granular Cell Tumor Involving Tongue: A Rare Case Report.

Granular cell tumor (GCT) is a rare benign tumor chiefly affecting the orofacial region, especially tongue. The origin of this neoplasia, after remaining a controversy for years, was finally identified to be from Schwann cell or neuroendocrine cell. They usually present as asymptomatic, firm, sessile, submucosal, solitary, or multiple nodule/papule like lesions. Histopathologically, the presence of sheets, cords or nests of large cells having abundant, eosinophilic granular cytoplasm, and pseudoepitheliomatous hyperplasia are the characteristic features of this neoplasm. Immunohistochemical stains such as S100, Cluster of differentiation 68, neuron-specific enolase, and laminin also aid in the proper diagnosis of granular cells. We hereby present a case of GCT in a 50-year-old male, which had a unique exophytic appearance, probably being only the second to be reported till date.

Clinical, radiological and histological features of an unique case of calcifying epithelial odontogenic tumor.

Calcifying epithelial odontogenic tumor (CEOT), also known as Pindborg tumor, is a rare benign but locally aggressive odontogenic neoplasm, accounts for <1% of all odontogenic tumors. CEOT is usually seen in the posterior area of the mandible in-between 30 and 50 years of age without definite sex predilection. A painless, slow-growing swelling with bone expansion is the most common clinical feature of CEOT. Radiographically, it presents as a mixed radiographic lesion may or may not be associated with any impacted tooth. Confirmation of the diagnosis is made by histopathological examination. The tumor has a recurrence rate of 10%-20% and so periodic follow-up is necessary. A unique case of CEOT involving the right mandibular molar-premolar in a 25-year-old female patient with clinical behavior, radiological, histopathological features and surgical managements is discussed herewith.

Langerhans Cell Histiocytosis in an Adult with Oral Cavity Involvement: Posing a Diagnostic Challenge.

Langerhans cell histiocytosis (LCH) is a rare hematological disorder characterized by local or generalized, uncontrolled proliferation and infiltration of Langerhans type of histiocytic cells. It represents a spectrum of clinicopathologic disorders, ranging from a highly aggressive and frequently fatal multisystem disease to an easily cured solitary lesion of bone. Involvement of children and the younger age group is more common than the adults. Oral cavity involvement occurs early in LCH, but the initial symptoms are generally nonspecific, often causing misdiagnosis. This report describes a rare case of chronic localized LCH in an adult patient, with involvement of oral cavity. A 34-year-old male patient presented with multiple nodulo-papular, ulcerated lesions in gingiva involving both the jaws (primarily mandible) and the left buccal mucosa, in addition to regional teeth mobility. The most striking feature was that even after extraction of mobile teeth, the lesions persisted. After recording proper history, performing clinical and radiological evaluation, an incisional biopsy was performed followed by histopathology and immunohistochemistry to reach a confirmatory diagnosis of LCH, thereby implementing early and appropriate initiation of treatment.

Surgical management of chronic hyperplastic candidiasis refractory to systemic antifungal treatment.

Chronic hyperplastic candidiasis (CHC), earlier known as candidal leukoplakia, is a variant of oral candidiasis that classically presents as a white patch on the commissures of the oral mucosa and it is mostly caused by Candida albicans. Clinically, the lesions are usually asymptomatic and regress after appropriate antifungal therapy and correction of the underlying cause. If the lesions are untreated, a small portion may develop dysplasia and later progress into carcinoma. The purpose of this article is to report a case of CHC in a 57-year-old male patient with a significant smoking habit, who presented with a thick, nonscrapable, brownish-white coating on the dorsum of the tongue for 9 years. This case is of particular importance and concern because of the high risk for malignant transformation in CHC. The role of biopsy and histopathology is also stressed through this case report in arriving at a definitive diagnosis and treatment planning. Further, this case is interesting because it was refractory to local and systemic antifungal treatment and so, surgery was chosen as an alternative treatment modality considering the side effects of the prolonged use of antifungal drugs.

Clinicopathological and histological behavior of mesenchymal chondrosarcoma involving maxilla.

Mesenchymal chondrosarcoma (MC) is a rare variety of chondrosarcoma (CS), which is both clinically unique and histologically distinct compared with conventional CS. Maxillofacial MCs are aggressive, have a tendency for recurrence and significant distant metastasis to lung and bone, and are associated with overall poor prognosis. Histopathologically, it is a biphasic tumor comprising of islands of hyaline cartilage with undifferentiated small round cells. Here, we present an interesting case of MC involving the left half of maxilla along with a brief review of the relevant literature.

Solitary Myofibroma of the Mandible in a Six-Year Old-Child: Diagnosis of a Rare Lesion.

Myofibroma is a benign uncommon fibroblastic tumour originating from the soft tissue, bone and may affect both children and adults. Radiographically myofibroma presents as unilocular radiolucency. Histologically, typical biphasic cellular arrangement is noted. Immunohistochemical markers are useful for definitive diagnosis of this uncommon neoplasm. Here, a case of six-year-old male child with a localized swelling in the left body of mandible is presented. The clinical, radiological, histological and immunohistochemical findings were corroborative of Infantile Myofibroma.

A unique case of clear cell variant of calcifying epithelial odontogenic tumor involving the maxilla.

Calcifying epithelial odontogenic tumor (CEOT) is a rare, benign, odontogenic tumor arising from the odontogenic epithelium and accounts for approximately 1% of all odontogenic tumors. Clear cell variant of CEOT is a distinct entity and has more aggressive biological behavior and higher chances of recurrence. Here, we present a unique case of clear cell variant of CEOT involving the left side of the maxillary alveolus in a 73-year-old female patient with thorough clinical, radiological, and histological details.

Clinical enigma: A rare case of clear cell odontogenic carcinoma.

Clear cell odontogenic carcinoma is a rare, aggressive neoplasm of the jaw with only 74 reported cases. It occurs predominantly in the mandibular anterior region during fifth to seventh decades of life. Clinically it manifests as intra-bony swelling with a variable degree of pain. Microscopically, it reveals nests of cells with clear cytoplasm in connective tissue stroma arranged in different patterns. It is often misdiagnosed due to the rarity of lesion and confusing histopathology. Immunohistochemical staining plays an intricate role to uncertain the native of the clear cell to reach a confirmative diagnosis. The article aims to highlight the clinicopathologic features of clear cell odontogenic carcinoma in a middle-aged man with special emphasis on its differential diagnosis.