Myospherulosis is a rare and poorly understood condition. The condition is initially suspected based on imaging findings, with confirmation requiring anatomopathological analysis. This lesion was first described in the United States in 1977, identified as spherules present in the anterior surgical regions of the nose, paranasal sinuses, and middle ear. The initial hypothesis proposed an infection by an unidentified endo-purulent fungus infection, perhaps due to the use of gauze soaked in antibiotics and non-sterile Vaseline. It was later suggested that these spherules were more likely altered red blood cells affected by lipid substances, leading to a granulomatous inflammatory reaction of the foreign-body type. We present the case of a 60-year-old patient with recurrent small subcutaneous nodules appearing in flare-ups since 2004. These painful purplish nodules evolved into ulcerations and bleeding. The lesions were accompanied by pain and functional weakness of the lower limb, that healed spontaneously. A long remission was reported after the prescription of antifungal treatment, which suggesting that an endosporulating fungal infection may have played a role in the pathophysiology of this lesion, alongside other contributing risk factors. Therefore, initiating antifungal therapy before surgical intervention may help improve the patient's prognosis.

Melanized focal changes (MFCs) in the fillet of farmed Atlantic salmon is a major quality concern. The changes are thought to initially appear as acute red focal changes (RFCs) that progress into chronic MFCs. Recent findings have indicated that hypoxia may be important in their development, possibly leading to necrosis affecting not only myocytes but also adipocytes. Thus, the aim of this study was to investigate possible hypoxic conditions in RFCs and the subsequent inflammatory responses and lesions in the adipose tissue in RFCs and MFCs. A collection of RFCs, MFCs and control muscle samples from several groups of farmed salmon was studied. Using immunohistochemistry, we found induction of the hypoxia-inducible factor 1 pathway in RFCs. Histological investigations of RFCs and MFCs revealed different stages of fat necrosis, including necrotic adipocytes, a myospherulosis-like reaction and the formation of pseudocystic spaces. Accumulations of foamy macrophages were detected in MFCs, indicating degradation and phagocytosis of lipids. Using in situ hybridization, we showed the presence of tyrosinase- and tyrosinase-related protein-1-expressing amelanotic cells in RFCs, which in turn became melanized in MFCs. In conclusion, we propose a sequence of events leading to the formation of MFCs, highlighting the pivotal role of adiposity, hypoxia and fat necrosis.

(1) Background: Use of Terra-Cortril may reduce pain and discomfort after tooth extraction. It is widely used among dentists, especially for third molar extraction and for treatment of dry socket. Only few case reports described unsuccessful healing with formation of myospherulosis. (2) Aim: The primary objective of this retrospective cohort study was to compare the occurrence of unsuccessful healing between extraction sockets locally treated with Terra-Cortril (TC) (exposure cohort) and extraction sockets subjected to unassisted healing (non-exposure cohort). The assessment of the three-dimensional morphology of the bone was a secondary objective. (3) Material and methods: The records of patients who had one or more extractions between 1 January 2020 and 1 July 2021 followed by implant placement in one private practice were retrieved and data were extracted. At the time of implant placement, practitioners established, both clinically and radiographically, if the healing was successful or unsuccessful. Explanatory demographic as well as clinical variables were extracted from patient files, checked and supplemented by contacting patients in cases of missing data. (4) Results: 69 patients were included who had, in total, 99 extractions. The exposure cohort included 55 sites, while the non-exposure cohort included 44 sites. A total of 56 sites demonstrated successful healing, and 53 showed unsuccessful healing. The regression model identified TC as a significant predictor (p = 0.014) for unsuccessful healing with an odds ratio of 2.86. Sites treated with Terra-Cortril had a significantly greater bone defect at level -1 mm, level -3 mm, and level -5 mm from the bone crest, and significantly greater maximal vertical and horizontal bone defects. At sites where Terra-Cortril was used, significantly more surgical consequences were reported (70.91% vs. 18.18%, p < 0.001). (5) Conclusions: fresh extraction sockets treated with Terra-Cortril increased the likelihood of unsuccessful healing with an odds ratio of 2.86. The greater defect size leads to significantly more limitations when planning implants at sites previously treated with TC.

Myospherulosis in the jaw is a rare, foreign body reaction that typically follows tooth extraction and the use of petrolatum-based medicaments. It appears as a radiolucency and can be mistaken for endodontic pathosis or other lesions without thorough clinical and radiographic evaluation as well as biopsy submission. Treatment is surgical removal and the recurrence is rare. This case report presents a unique finding of a posterior mandible multilocular radiolucency appearing as an apical lesion on 2-dimensional panoramic imaging until visualized with 3-dimensional imaging. Clinical testing and patient referral led to a biopsy and diagnosis of myospherulosis. This is the first case report of myospherulosis presented in the endodontic literature.

Myospherulosis develops as the result of a reaction between exogenous lipids and red blood cells (RBC) of the patient, being the latter injured when perceived as a foreign body by the immune system, triggering an intense inflammatory response. A 63-year-old man with a history of dyslipidemia, Barret's esophagus, and coronary disease, who was taken to thoracoscopy and left inferior lobectomy due to the presence of a pulmonary mass. A primary pulmonary adenocarcinoma was diagnosed. On follow up a PET-CT was performed, in which a metabolically active lesion was described adjacent to the prior lobectomy, suggesting a local relapse. EBUS-TBNA was then performed, obtaining a sample from which histopathological pattern compatible with myospherulosis was obtained. Although it is a rare entity, myospherulosis has a well-defined morphological pattern. By not recognizing myospherulosis as a benign lesion, a patient's risk of invasive cancer can be overestimated. It is a phenomenon found with increasing frequency and has been reported in different tissues, however, this is the first report in the literature of myospherulosis of the lung. Greater awareness is required regarding the existence of this phenomenon.