Torsion or volvulus of the gallbladder is a rare situation that rapidly progresses to gangrene and linked with a poor prognosis, even death, if unrecognized and untreated. An interesting and rare case of gallbladder volvulus in which diagnosis was obtained by comparing CT images and HIDA scan with SPECT-CT is presented. Relevant literature is reviewed, and recommendations are outlined.

Osteochondritis dissecans (OCD), first described in 1870 by Paget (Ananthaharan & Randsborg, 2018;Edmonds & Polousky, 2013), is a disorder affecting articulations and is characterized by the sterile osteonecrosis of subchondral bone. This condition is not uncommon as the incidence is reported to be 11.5/100 000 in patients 18 years old or younger (Ananthaharan & Randsborg, 2018). The natural history of OCD in developing children has been well studied and the majority of OCD lesions heal spontaneously in patients with open growth plates (Bellelli et al., 2001). When OCD does not resolve, an osteochondral fragment can separate from the articular surface and lead to a "loose body" in the joint space and possibly precipitate osteoarthritis (Gibson & Briggs, 2016). Patients affected by this disease usually present with activity-related pain, "locking" mechanical symptoms, and stiffness in the articulation (Gkourogianni et al., 2017).

Osteochondritis dissecans (OCD) is a chronic disease of the articular cartilage characterized by focal lesions of subchondral bone and overlaying cartilage. Through the growing number of reports describing the high prevalence of OCD in some families, the subcategory termed familial OCD (FOCD) was established. With the development of genetic approaches such as genome-wide association studies and sequencing, aggrecan (ACAN) has been identified as one of the genes of interest associated with FOCD. Aggrecan is a crucial protein for the preservation and function of cartilage. However, due to FOCD being characterized relatively recently, there is a paucity of literature on the subject. The purpose of this review is to explore the relationship between ACAN mutations and familial OCD as well as to explore current treatment options and avenues for future research. In vitro and animal studies have shown the importance of ACAN in the preservation of cartilage. However, the only human ACAN mutation related to OCD ever identified is a V2303M mutation in the G3 domain. Multiple treatments have been superficially explored, and some options such as growth hormone (GH) and gonadotrophin-releasing hormone agonists (GnRHa) show potential. Thus, further research on FOCD in needed to identify other ACAN mutations and determine optimal treatment modalities for this patient population.

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