Background: Interstitial granulomatous dermatitis with arthritis, or Ackerman's syndrome, is characterized by inflammatory articular flares of potentially destructive outcome and cutaneous lesions of varied patterns: cord-like lesions on the flanks or violaceous plaques on the trunk and limbs. Histologically, the main features are histiocytes laminated between collagen fibres, sometimes organized in rosettes comprising tiny granulomas surrounding fibres of homogeneous aspect.
Case reports: Four patients fitting this description were investigated. Cutaneous lesions displayed various patterns: cord-like lesions (one patient), brown plaques on the flanks edged with papules (one patient), grossly annular violaceous plaques on the back (one patient), and infiltrated plaques on the palms and thighs (one patient). Joint symptoms were present in all cases (one seropositive rheumatoid arthritis and one seronegative rheumatoid arthritis, both already known; acute rheumatoid arthritis in two cases). The histological pattern was quite similar in all cases, with laminated histiocytes in palisading layers mixed with swollen collagen fibres; "rosette" figures were present in two cases. Autoimmune response was seen with antinuclear antibodies (two cases) and/or rheumatoid factor (two cases). The short-term outcome of cutaneous lesions was rapidly favourable in most cases with systemic steroids (one case) or Non Steroidal Anti-Inflammatory Drugs (one case), and spontaneously in one case.
Comments: This entity, defined by the presence of inflammatory arthritis and cutaneous lesions of various clinical types, either more specific but infrequent (cord-like), or less specific but more frequent (plaque-like), and featuring a peculiar histological pattern, chiefly affects women aged between 30 and 80 years. Pathophysiological mechanisms and nosological borders are debatable and authors consider this condition as either an autonomous disease or else a mere subset of vasculitis with palisading granulomas in collagen vascular disorders, despite the rarity of authentic vasculitis. A setting of autoimmunity is frequently present. Furthermore, a fairly similar histological pattern is sometimes seen in some lesions forming a subset of cutaneous side-effects of drugs. Articular outcome may be unfavourable with joint destruction in more than half of patients, whether or not in a setting of rheumatoid arthritis. Spontaneous resorption can occur. Treatment has not yet been codified and is based primarily on anti-inflammatory drugs.