Panniculitis

Introduction Panniculitis The subcutaneous fat layer consists of interstitial spaces between the lobules and lobules of fat cells. According to the main site of inflammation, panniculitis can be divided into two categories: lobular panniculitis and septal panniculitis. Lipitis is a broad-spectrum syndrome that can be divided into different subtypes depending on clinical characteristics, related diseases, and pathological changes. Diagnosis In addition to discovering the disease and pathogens that are caused, the earliest fresh live sputum, it is important to remove a sufficient amount of specimens and perform a series of pathological sections (scheduled, lobular or mixed).

Cause

It can be divided into different subtypes according to clinical characteristics, related diseases and pathological changes. More complex, local factors such as trauma, cold, injection of certain drugs, systemic factors such as tuberculosis infection, tonsillitis can cause panniculitis, some systemic diseases such as lupus erythematosus, scleroderma, sarcoidosis can also cause lipids Membrane inflammation. Lesions of subcutaneous fat vessels often affect the lipid membrane and cause inflammatory changes.

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Clinical manifestations of panniculitis:

Symptoms and signs of lipid membrane: clinically acute or subacute, characterized by repeated general malaise, joint pain, fever, subcutaneous nodules. Nodular panniculitis can be divided into skin type and system type according to the affected part.

(1): Nodular panniculitis Skin type: the lesion only invades subcutaneous fat tissue, but does not involve the internal organs. It is characterized by subcutaneous nodules in clinic. The subcutaneous nodules vary in size, and the diameter is generally 1 ~ 4 cm. Up to 10 cm or more. In a few weeks to a few months, the clusters appear symmetrically, which occurs in the thighs and calves, and can also affect the upper arms, occasionally on the torso and face. The surface of the skin is dark red with edema and can also be normal skin color. The subcutaneous nodules are slightly higher than the skin surface. The texture is firmer and may have spontaneous pain or tenderness. When the nodular panniculitis is located deep in the skin, it can move slightly. When it is shallow, it adheres to the skin and has little activity.

Nodular panniculitis recurrent and the interval varies. After the nodules have subsided, local skin has varying degrees of depression and hyperpigmentation, which is atrophic scars that remain due to fat atrophy and fibrosis. Some nodules can rupture on their own, and the yellow oily liquid flows out. This is called "Liquefying panniculitis". It occurs mostly in the thigh and lower abdomen, and the calf is rarely seen. An irregular scar is formed later.

More than half of the skin type patients with panniculitis are accompanied by fever, which may be low fever, moderate heat, or high fever. The heat type is mostly intermittent heat or irregular heat, and a few are relaxation heat. Usually, fever occurs after a few days of subcutaneous nodules, and the duration is uncertain. It gradually decreases after 1~2 weeks, which may be accompanied by fatigue, muscle aches, loss of appetite, and joint pain in some cases. It is more common in knee and ankle joints. Symmetry, persistence or repeatability, the joints may be red and swollen, but no joint deformities. Most patients can gradually relieve within 3 to 5 years, and the prognosis is good.

(2): Systemic panniculitis: In addition to the above-mentioned skin type performance, there is also visceral involvement. Visceral damage can occur at the same time as skin damage, and can also occur after skin lesions. In a few cases, fat damage occurs before skin lesions. Various organs can be affected, including liver, small intestine, mesentery, omentum, retroperitoneal adipose tissue, bone marrow, lung, pleura, myocardium, pericardium, spleen, kidney and adrenal gland. The fever of systemic panniculitis is generally special, often parallel with the appearance of rash, mostly for heat, and the heat gradually rises after the appearance of rash, which can be as high as 40 ° C, and gradually decreases after 1 to 2 weeks.

Digestive system involvement is more common, and can cause hypochondriac pain, hepatomegaly, fatty liver, jaundice and liver dysfunction when liver damage occurs. Invasion of mesenteric, omentum, retroperitoneal fat tissue, abdominal pain, abdominal distension, abdominal mass, intestinal obstruction and gastrointestinal bleeding. Bone marrow involvement can lead to a complete reduction in blood cells. Respiratory system involvement can lead to pleurisy, pleural effusion, hilar shadows, and transient masses in the lungs. A transient renal insufficiency can occur with the kidneys involved. Involving the central nervous system can lead to mental disorders or mental disorders. The prognosis of panniculitis is poor, and people with extensive visceral involvement may die from multiple organ failure, or major bleeding in the upper digestive tract or infection with nodular panniculitis.

Differential diagnosis

1. Clinical features:

(1) It is good for young women.

(2) It is characterized by recurrent episodes and subcutaneous nodules that appear in batches. After the nodules have subsided, local skin appears to have varying degrees of depression and pigmentation.

(3) often accompanied by systemic symptoms such as fever, joint pain and myalgia.

(4) When the lesion invades the visceral adipose tissue, depending on the affected part, different symptoms appear. If the viscera is widely affected, multiple organ failure, major bleeding, or concurrent infection may occur.

2. Pathological diagnosis: skin nodule biopsy, its histopathological changes are the main basis for diagnosis, it can be divided into three phases:

(1) Phase I (acute inflammatory phase): Degeneration and necrosis of adipose tissue in the lobules, infiltration of neutrophils, lymphocytes and histiocytes, with some changes in vasculitis.

(2) Phase II (phagocytic phase): A large number of macrophage infiltrates in the degenerating necrotic adipose tissue, phagocytizing denatured fat cells, forming a characteristic "foam cell".

(3) Phase III (fibrosis phase): Foam cells are largely reduced or eliminated, replaced by fibroblasts; the inflammatory response is replaced by fibrous tissue, and finally fibrosis is formed.

3, according to the above clinical and histopathological characteristics can be diagnosed, but need to be identified with the following diseases:

(1) Nodular erythema: subcutaneous nodules with symmetric distribution may also occur, but the nodules are mostly confined to the calf extension side, which does not collapse, and resolves spontaneously after 3 to 4 weeks, and there is no atrophic scar after healing. The systemic symptoms are mild and there is no visceral damage. Secondary to other systemic diseases (such as Behcet's disease, etc.), accompanied by symptoms of related diseases. Pathological manifestations of septal panniculitis with vasculitis.

(2) Hard erythema: mainly occurs in the middle and lower part of the flexor of the lower leg, the pain is lighter, but it can be broken to form an ulcer that is difficult to heal. Histopathology showed tuberculous nodules or tuberculous granuloma with significant vasculitis changes.

(3) tissue phagocytic panniculitis: subcutaneous nodules, repeated fever, liver and kidney dysfunction, whole blood cell reduction and bleeding tendency, etc., but the general condition is critical, progressively worse, and eventually die of bleeding. Histopathological changes can occur in so-called "bean-like" tissue cells that phagocytose various blood cells and their fragments, which can be distinguished from the disease.

(4) Nodular polyarteritis: common skin lesions are also subcutaneous nodules, which can form necrosis at the center, but the nodules are distributed along the artery. Visceral damage is most common in the kidney and heart, and peripheral nerve involvement is very common. Peripheral neutrophil cytoplasmic antibody (P-ANCA) and hepatitis B surface antigen positive have diagnostic value, pathologically confirmed small and medium arterial necrotizing vasculitis, arterial wall granulocyte and monocyte infiltration.

(5) Subcutaneous lipid-like T-cell lymphoma: hyperthermia, hepatosplenomegaly, whole blood cell reduction and bleeding tendency, which is very similar to systemic nodular panniculitis. However, there are tumor cell infiltration in adipose tissue, which are small and medium polymorphic T cells. The intermediate torsion nucleus and cerebral gyrus nucleus have important diagnostic value, and often reactive phagocytic tissue cells appear. Immunohistochemistry was positive for CD45RO and CD4, while CD20 was negative.

(6) malignant histiocytosis: similar to systemic nodular panniculitis, showing hyperthermia, hepatosplenomegaly, whole blood cell reduction, erythema, subcutaneous nodules, etc., but tissue cells are abnormally shaped, and multinuclear giants can appear Abnormal tissue cells, the condition is more dangerous, and the prognosis is extremely poor.

(7) Subcutaneous lipid granulomatosis: skin damage nodules or plaques, 0.5~3cm, the larger ones can reach 10~15cm, the quality is hard, the surface skin is light red or normal skin color, light tenderness, distributed on the face The torso and limbs are common to the inner side of the thigh and can gradually retreat after 0.5 to 1 year, without leaving atrophy and depression. No systemic symptoms such as fever. The early pathological changes were the cystic inflammation of the fatty lobule, with degeneration and necrosis of fat cells, infiltration of neutrophils, histiocytes and lymphocytes, fibrosis in the late stage, and cystic cavities of different sizes in the tissues. The disease occurs in children, nodules scattered, no atrophy and depression after regression, no systemic symptoms, there is a tendency to self-healing.

(8) Post-lipid steroids: patients with rheumatic fever, nephritis or leukemia have a large number of glucocorticoids in the short-term, subcutaneous nodules within 1 to 13 days after glucocorticoid reduction or discontinuation, nodules 0.5 ~4cm in size, the surface of the skin is normal or congested, it occurs in the most part of the accumulation of subcutaneous fat caused by the application of glucocorticoids, such as the cheeks, jaw, upper arm and buttocks, can fade after weeks or months , no systemic symptoms, such as hormone addition or re-use after re-use can also promote nodular regression. Most cases have no systemic symptoms. The disease is now visible in the fat lobules, and there are foam cells, tissue cells and foreign body giant cells infiltrating and denatured fat cells appear and see needle-shaped fissures. There is no special treatment for this disease, and the skin lesions can be self-resolved without scars.

(9) Cold panniculitis: This disease is a kind of physical panniculitis caused by cold direct damage to adipose tissue. It is manifested as subcutaneous nodular damage, which occurs mostly in infants and young children. Adults are more common in patients with frostbite. Or those with poor blood circulation caused by tights.

The disease occurs in the winter, after a few hours or 3 days of cold, subcutaneous nodules appear on exposed parts such as the face and limbs, the diameter of 2 ~ 3cm, can also increase or fuse into plaque, hard, tender, It is purple and can gradually fade away without leaving traces. The main pathological change is acute fat necrosis.

(10) Others: It is also necessary to distinguish from subcutaneous fat necrosis caused by pancreatic panniculitis (pancreatitis and pancreatic cancer), leprosy, trauma or foreign body. In addition, it is necessary to exclude a1 anti-trypsin deficiency panniculitis, steroid hormones and post-lipiditis.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.