[Figure - 1],[Figure - 2]

Diagnosis : Bacillary Angiomatosis

Histopathological findings

[Figure - 3] shows H and E stained section demonstrating a dermal vessel lined with protuberant endothelial cells surrounded by myxoid connective tissue containing neutrophils and amphophilic granular material. On Warthin-Starry staining [Figure - 4], multiple clumps of tangled, dark, silver-staining bacillary organisms were seen. Other organisms that stain positive with Warthin-Starry silver stain include Legionellae species, Nocardia species, Trophermyma whippleii , Treponema pallidum , Borrelia burgdorferi and Helicobacter pylori . Solid areas of spindle cells may also be present, which in some cases mimic Kaposi sarcoma or other sarcomas.

Discussion

Bacillary angiomatosis (BA), also known as epitheliod angiomatosis, is the vascular proliferative form of infection with small gram-negative Bartonella organisms. It was first described in an HIV-positive patient. Cutaneous lesions result from B. henselae and B. quintana infections, while visceral involvement is almost exclusively caused by infection with B. henselae . BA most commonly affects skin and subcutaneous tissue. Subcutaneous lesions may erode into underlying bones (i.e., osseous bacillary angiomatosis), especially the tibia, fibula and radius. Rarely, skeletal muscles may be involved, resulting in pyomyositis. ^[1]

Most patients are infected with HIV and have CD4 ⁺ cell counts of less than 200/mm ³ . A major challenge in the diagnosis of cutaneous BA is the diverse presentation of lesions. Patient may present with raised red or purple rubbery lesions in the skin that have an obvious vascular appearance and an erythematous base and may bleed profusely when traumatized. Similar lesions are present in the oral mucosa, tongue, nose, penis or anus. Cutaneous lesions may take one of the following forms: (1) solitary or multiple red, purple, flesh-colored hemangioma-like papules; (2) nodules, often covered with a fine tightly adherent scale, mainly seen in subcutaneous variety; (3) large, friable, pedunculated or polypoid exophytic masses; or (4) hyperpigmented, hyperkeratotic, indurated plaques, typically on extremities, often overlying osseous defects. Lesions may develop ulceration, discharge, crusting and are tender and may be associated with regional lymphadenopathy. BA also may have the appearance of a cellulitic plaque. ^[2] Bone pains are frequent in the forearms or legs. Patient may have symptoms resulting from visceral involvement, including abdominal pain, vomiting, jaundice, tenesmus and bloody diarrhea (colonic bacillary angiomatosis); psychiatric symptoms and difficulty in breathing secondary to laryngeal obstruction. Underlying disease conditions may include HIV organ transplantation, leukemia or chemotherapy. The clinical differential diagnosis of cutaneous lesions includes Kaposi sarcoma (KS), pyogenic granuloma, a number of subcutaneous tumors, angiosarcoma, histoplasmosis, sporotrichosis, etc. The diagnosis of cutaneous BA is most often based on clinical features coupled with biopsies of lesions and appropriate tissue staining.

Treatment recommendations are based on retrospective studies. Erythromycin remains the drug of choice. Tetracyclines are the first alternative. A combination of doxycycline (100 mg o.d.) plus rifampicin (300 mg b.i.d.) may be used in patients with severe disease who are immunocompromised. Bartonella Clarithromycin, azithromycin, chloramphenicol, ciprofloxacin, trimethoprim-sulfamethoxazole, rifampin, isoniazid and gentamicin combined with either doxycycline or ciprofloxacin produce good clinical responses. It is noteworthy that our patient developed BA while on ATT. A reaction resembling the Jarisch-Herxheimer reaction has been described upon the initiation of appropriate antibiotic therapy. The optimal duration of therapy is not known, but the cutaneous lesions resolve substantially after approximately 4-7 days of therapy and usually completely after 1 month. Patients with HIV infection may require lifelong therapy if relapses occur. Cryotherapy, electrodessication and curettage and surgical excision of solitary cutaneous lesions can be useful as adjunctive therapy. ^[1]

Prevention of bacillary angiomatosis associated with B. henselae infection involves avoidance of cat contact, while with B. quintana infection involves delousing procedures. Use of macrolides for Mycobacterium avium-intracellulare prophylaxis in patients infected with HIV is protective against bacillary angiomatosis. Prognosis of bacillary angiomatosis itself is excellent because antibiotics are curative in most patients. Medical/Legal pitfalls include failure to distinguish KS (potentially life threatening) from BA. ^[1]