Lipomembranous changes associated with systemic lupus erythematosus

Delayed post-traumatic alopecia of the dorso-lumbar area following a road accident in a cat without pelvic fracture

An 11-month-old female, neutered domestic short-haired cat was presented for non-pruritic alopecia of the dorso-lumbar area which had appeared 1 month after a road accident. After the trauma, a fracture of the left hind limb was demonstrated without dermatological lesions on the dorso-lumbar area. One month later, hair loss was observed in this area. Four months later, clinical examination revealed dorso-lumbar alopecia. Histopathological findings included an absence of all adnexae, a mild fibroplasia and fibrosis without oriented collagen deposition, individual to coalescing pyogranulomas at the dermo-hypodermal junction and a moderately stenotic hypodermal artery. Clinical history, physical examination and histopathological findings were compatible with post-traumatic dorso-lumbar alopecia. Special features of this case include the location of the fracture and the more developed histopathological lesions with pyogranulomas at the dermo-hypodermal junction, the absence of hair follicles and a stenosing arteriopathy.

Lipomembranous fat necrosis: A distinctive and unique morphology (Review)

Lipomembranous fat necrosis (LFN) is an uncommon but distinct form of fat necrosis, which is characterized by eosinophilic, crenulated and/or serpiginous membranes. LFN exhibits macrocystic, microcystic and/or crushed features. LFN is routinely detectable on hematoxylin and eosin (H&E)-stained sections, and is present both in the acute phase and in the later or fibrous stage of necrotic fatty lesions. Smaller crushed LFN embedded within fibrous tissues may be difficult to recognize on H&E-stained sections, but can be highlighted by some staining techniques, including Masson trichrome, periodic acid-Schiff, orcein, long Ziehl-Neelsen stain, silver impregnation, phosphotungstic acid-hematoxylin and luxol fast blue staining. LFN was initially considered a specific feature of Nasu-Hakola disease, but has since been identified in various subcutaneous or intraabdominal lesions related to ischemic conditions or venous insufficiency. In addition, LFN is detectable in intra-articular loose bodies and aortic valves with or without dysfunction, suggesting that LFN is also associated with ischemia-like hypoxic conditions or malnutrition. LFN is considered to be a histological hallmark of hidden ischemic or hypoxic/malnourished conditions in various diseases; however, the exact mechanisms of LFN remain poorly understood. The present review described the clinicopathological features of this interesting, but poorly characterized, condition.