What is Lobular Panniculitis?
Lobular panniculitis refers to a type of inflammation that affects the lobules of the subcutaneous fat. It is a condition characterized by the involvement of the fat lobules without significant inflammation of the septa. This distinguishes it from septal panniculitis, which primarily affects the septa between the fat lobules.
Histological Features
Histologically, lobular panniculitis presents with a variety of features depending on the underlying cause. Commonly, one can see infiltration of inflammatory cells such as neutrophils, lymphocytes, and macrophages within the fat lobules. There may also be evidence of fat necrosis, which is characterized by the presence of necrotic adipocytes with a ghost-like appearance. In some cases, multinucleated giant cells and lipophages (macrophages that have ingested lipid) can be observed.Common Causes
Lobular panniculitis can be caused by a variety of factors including infections, autoimmune diseases, and physical trauma. Infections such as bacterial or fungal infections can lead to acute inflammation within the fat lobules. Autoimmune diseases like lupus erythematosus and sarcoidosis can also manifest as lobular panniculitis. Moreover, physical trauma or cold exposure can precipitate this condition.Clinical Presentation
Clinically, patients with lobular panniculitis often present with tender nodules or plaques in the subcutaneous tissue. These lesions are commonly found on the lower extremities but can occur anywhere on the body. The overlying skin may be erythematous or normal in appearance. In chronic cases, the nodules may become firm and scarred.Diagnosis
The diagnosis of lobular panniculitis is primarily based on histological examination of a skin biopsy. This involves taking a sample of the affected tissue and examining it under a microscope. Special stains and immunohistochemical techniques may be employed to identify specific infectious agents or to highlight particular inflammatory cells. Other diagnostic tools such as imaging studies and laboratory tests may be used to identify underlying systemic diseases.Management and Treatment
The management of lobular panniculitis depends on the underlying cause. In cases where infection is the cause, antibiotic or antifungal therapy may be required. For autoimmune-related panniculitis, immunosuppressive drugs such as corticosteroids may be used. Supportive care including pain management and measures to reduce inflammation, such as nonsteroidal anti-inflammatory drugs (NSAIDs), can also be beneficial.Prognosis
The prognosis of lobular panniculitis varies depending on the etiology. In cases where the underlying cause can be effectively treated, the prognosis is generally good. However, chronic or recurrent panniculitis can lead to permanent changes in the subcutaneous tissue including fibrosis and atrophy.Conclusion
Lobular panniculitis is a histologically distinct condition characterized by inflammation of the fat lobules. It can be caused by a variety of factors and presents with tender subcutaneous nodules. Diagnosis is primarily made through histological examination, and treatment is tailored to the underlying cause. Understanding the histological features and clinical implications of lobular panniculitis is crucial for effective diagnosis and management.
