Inflammatory nodules of the lower legs: a clinical and histological analysis of 134 cases in Korea

Panniculitis: A summary

The diagnosis of panniculitis is felt to be a confusing topic by some pathologists. This summarical article presents inflammatory diseases of the subcutis in a systematic fashion, based on whether they are centered on fibrovascular septa or the adipose lobules, and whether morphologic vasculitis is present or not. Septocentric, non-vasculitis disorders include erythema nodosum, panniculitis that follows the use of "biological" therapeutic agents, lipodermatosclerosis, post-irradiation panniculitis, morphea profunda, and necrobiosis lipodica profunda. Polyarteritis nodosa and Behçet's disease are the conditions that are based in the subcutaneous septa with vasculitis. Predominantly-lobular panniculitides with no vasculitis include pancreatogenic panniculitis, the panniculitis of alpha-1-antitrypsin deficiency, panniculitis associated with lupus erythematosus and dermatomyositis, subcutaneous Sweet syndrome, eosinophilic panniculitis, factitial panniculitis, cold panniculitis, panniculitis following injections of corticosteroids, lipomembranous (ischemic) panniculitis; sclerema neonatorum and subcutaneous fat necrosis of the newborn, and Rosai-Dorfman disease of the subcutis. Erythema induratum and infectious panniculitis are vasculitic and lobulocentric conditions. This article reviews the histological features of these diseases.

Inflammatory nodules of the leg

There is a group of diseases characterized by inflammatory nodules which generally located on the lower leg. They have certain clinical appearances in common, which often makes a differential diagnosis difficult or impossible on clinical grounds alone. There is a great variation in histopathologic appearance, which depends on the duration of the lesions and sites from specimens are obtained for biopsy. Therefore, separating and subclassifying inflammatory nodule lesions of the legs, based on the subtle clinical and histological variation, is not easy. Despite all these difficulties, a specific diagnosis can be made with an adequate clinic-pathologic correlation.

Tender cutaneous nodules of the legs: diagnosis and clinical clues to diagnosis

BACKGROUND

"Tender cutaneous nodules of the legs" is a common manifestation in dermatology. Histopathological investigation is usually required for this condition, because clinical data are frequently insufficient to make a definite diagnosis.

OBJECTIVE

To identify and analyze the causes of patients presenting with tender leg nodules and to reveal clinical clues that could help to differentiate causes.

MATERIALS AND METHODS

The medical records and histopathological slides of patients presenting with tender cutaneous nodules of the legs between January 2005 and December 2007 were retrospectively reviewed.

RESULTS

Of the total of 154 patients, 122 (79.2%) were female. Definite diagnoses were categorized into four groups: inflammation (84.4%); infection (5.8%); tumor (6.5%); and nonspecific (3.2%). The most common cause in the inflammation group was erythema nodosum. The infections found were Acremonium spp., Penicillium sp., Mycobacterium abscessus, Mycobacterium fortuitum and Mycobacterium leprae. The tumors included leiomyoma, leukemia cutis, and lymphomas. Clinical data that correlated with and could be used as clues for the inflammation group were female sex (P = 0.03, OR 6.43) and lower leg involvement (P = 0.03, OR 7.14).

LIMITATIONS

The retrospective manner of this study is a limitation.

CONCLUSION

Various inflammatory conditions, infections, and tumors can present as tender cutaneous nodules of the legs. Female sex and lower leg involvement were clinical data that could be used as clues for the diagnoses in the inflammation group. However, histopathological investigation is still crucial to determine a definite diagnosis in patients presenting with tender cutaneous nodules of the legs.

Panniculitis: an unusual cutaneous manifestation of rheumatoid arthritis

Specific and nonspecific panniculitis may occur during the course of connective tissue diseases. However, association of panniculitis and rheumatoid arthritis has only rarely been described, and with so few reports, it is difficult to know the significance of this unusual association. We describe 2 patients with rheumatoid arthritis and features of Sjögren syndrome in whom panniculitis developed during the course of the disease. Histologic confirmation of septal panniculitis was established in one case and the panniculitis in this case improved as the arthritis resolved.

Neutrophilic lobular (pustular) panniculitis associated with rheumatoid arthritis: a case report and review of the literature

Rheumatoid nodules, which affect the subcutis around joints, are the most frequent specific cutaneous lesions of rheumatoid arthritis (RA). Panniculitis is a rarely reported and nonspecific complication of RA. We report a 42-year-old woman with seropositive RA who presented with a 2-month history of lower leg panniculitis. Biopsy of a leg nodule showed a lobular neutrophilic infiltrate with lipophages and central basophilic necrosis. In addition, focal changes of lipomembranous fat necrosis indicative of ischemic damage were identified at the margins of the lobular infiltrate. Neutrophilic lobular panniculitis is commonly detected in panniculitis secondary to bacterial infections, pancreatitis, and factitial causes. However, this pattern of panniculitis has also been reported in some cases of erythema nodosum-like lesions found in Behçet disease or bowel bypass syndrome and in rare cases of seropositive RA. These reported histologic findings fall into the spectrum of neutrophilic vascular reactions described by Jorizzo and Daniels for RA-associated dermatoses. In view of these findings. RA and related neutrophilic dermatoses (e.g., Behçet disease) should be included in the differential diagnosis of neutrophilic lobular panniculitis.