Dilated Odontoma Arising in the Mandibular Third Molar Germ: Report of a Case of an Unusual Lesion in an Uncommon Site

Dilated odontoma is the most severe variant of dens invaginatus. It is extremely uncommon in the posterior mandible. It is thought to originate during the morpho-differentiation stage of dental development. However, its etiology and pathogenesis remain obscure. We report here the clinical and pathologic findings of an incidentally discovered dilated odontoma arising in the left third mandibular molar germ of an 11-year-old male and a review of the pertinent literature. As dilated odontoma is not established as an independent entity in the current WHO classification of odontogenic tumors and is the result of a well-established developmental anomaly of the tooth (that is, the invagination of the enamel organ into the dental papilla), it should be better identified as dilated dens invaginatus.

Diffuse Subamniotic Calcification: A Novel Pattern of Placental Calcification

Two primary patterns of placental calcification have been described, each with distinctive pathophysiology and clinical relevance. We report a novel pattern of diffuse subamniotic calcification. It occurred in a 25-week placenta involved by recurrent chronic histiocytic intervillositis (CHI) associated with severe intrauterine growth restriction (IUGR) and intrauterine fetal demise (IUFD). This was the mother’s third stillbirth related to CHI, despite treatment with intravenous immunoglobulin (IVIG), prednisone, low-molecular-weight heparin, and acetylsalicylic acid (ASA). On placental examination, the majority of the fetal surface was calcified. This variably formed a continuous band or dispersed calcium microparticles. Electron microscopy demonstrated associated electron dense deposits highly suggestive of immune complex deposition. CHI explains recurrent IUGR and stillbirth, but has not been associated with calcification or immune complex deposition. We hypothesize IVIG therapy may have caused immune complex deposition and subsequent dystrophic calcification, supported by its rare association with immune complex deposition disorders in the kidney. Identification of additional cases with this pattern of calcification, with additional studies on fresh tissue including immunofluorescence, electron microscopy and mass spectrometry, may aid in elucidating the underlying pathophysiology and clinical significance of this unusual lesion.

Unusual lesion in the splenium of the corpus callosum and coronavirus infectious disease-19

Coronavirus infectious diseases (COVID-19) is an emerging infectious disease that has taken a strong grip on the entire global community. The diagnosis per se is straightforward; however, the disease seems to affect multiple organs. Cytokine-storm, increased thromboembolic state, deranged overall homeostasis and aggressive medical treatment can cause a variety of lesions in the central nervous system. Interpretation of brain imaging findings will require a thorough understanding of the clinical status of the patient and treatment being offered, keeping in mind the several ways in which the viral pathogen, severe acute respiratory syndrome coronavirus-2 may interact with brain tissue. We present differential diagnosis of a MRI identified solitary lesion in the splenium of the corpus callosum, in a COVID-19 positive patient with altered mental status.