Actinomyces-Induced Inflammatory Pseudotumor of the Lymph Node Mimicking Scrofula
From University of Chicago, Chicago, IL 60637.
Background: Inflammatory pseudotumor is a rare condition characterized by an aberrant immunologic response that manifests as tumor-like masses in various anatomical locations. Two previous case reports described Actinomyces as a trigger for abdominal inflammatory pseudotumor (1, 2).
Objective: To report what we believe is the first case of Actinomyces-induced inflammatory pseudotumor with primary lymph node involvement.
Case Report: A 34-year-old woman with a history of systemic lupus erythematosus presented to an outpatient clinic with painful swelling on the left side of the neck, a 7-day history of temperatures up to 39.4 °C, and a 3-day history of cough. Her systemic lupus erythematosus was controlled with methotrexate and hydrochloroquine. She received antibiotic therapy for presumed lymphadenitis.
She returned to the clinic 3 days later with no improvement in her symptoms. At that time, physical examination was notable for a firm, tender left submandibular mass without erythema or fluctuance and decreased breath sounds at the right lung base. Chest computed tomography showed a consolidation in the right lower lobe (Figure, A). Further history revealed that the patient had a positive purified protein derivative test several years earlier but did not begin antituberculous therapy. She was admitted to the hospital for suspected reactivation mycobacterial tuberculosis causing pneumonia and lymphadenopathy (scrofula).
Figure. Actinomyces-induced inflammatory pseudotumor with primary lymph node involvement.
A. Noncontrast coronal computed tomographic scan of the lungs showing right lower-lobe consolidation. B. Biopsy specimen of the lymph node showing broadening of connective tissue framework of the lymph node (pale areas) (hematoxylin–eosin stain; original magnification, × 40). C. Higher-magnification view of panel B showing expansion of sclerosed mesenchymal tissue in the trabeculae of the lymph node with proliferation of spindle cells, vessels, and inflammatory cells (hematoxylin–eosin stain; original magnification, × 400).
Fine-needle aspiration biopsy of the lymph node showed reactive features. Transbronchial biopsy of the lung lesion showed chronic inflammation without granulomas. Neither biopsy culture yielded fungal or bacterial growth, including acid-fast bacilli. Results of tests for legionella, histoplasma, and blastomycosis antigen were negative.
Pathologic examination of an excisional biopsy specimen of the lymph node revealed preserved architecture with focal paracortical hyperplasia and inconspicuous lymphoid follicles. In addition, there was expansion of the capsule, trabeculae, and hilum by sclerosed mesenchymal tissue that contained scattered spindly and polygonal cells; small blood vessels; and inflammatory cells, including plasma cells, histiocytes, and lymphocytes, without evidence of organisms, granulomas, or necrosis (Figure, B and C). Immunohistochemistry revealed no phenotypical abnormalities. These findings were consistent with inflammatory pseudotumor of the lymph node (3).
The patient began methylprednisolone therapy, and her neck swelling decreased substantially. After 12 days, the culture from her biopsy specimen yielded Actinomyces species. She started a 12-month course of amoxicillin therapy. Methylprednisolone therapy was switched to prednisone therapy, and she was discharged receiving a regimen of prednisone with a plan to taper the dosage over 3 months. Three months later, she was asymptomatic and repeated computed tomography showed complete resolution of her lung lesion.
Discussion: Inflammatory pseudotumor is a histologic diagnosis characterized by a proliferation of myofibroblasts with an infiltrate of inflammatory cells, such as lymphocytes, histiocytes, and plasma cells (3, 4). Affected patients commonly present with constitutional symptoms and masses in the lungs, spleen, liver, gastrointestinal tract, bladder, orbit, or lymph nodes (4). Inflammatory pseudotumor encompasses a wide spectrum of conditions, including inflammatory myofibroblastic tumor, plasma cell granuloma, or xanthofibroma (5).
Inflammatory pseudotumor may be a primary immunologic lesion in some cases and a reaction to an infection in others. In rare cases, this condition has been linked to neoplastic processes. Inflammatory pseudotumor of the lymph node is a reactive process centered on the connective tissue framework of the lymph node (3). The disease course is usually benign, and this condition is managed with excision or steroids plus treatment of any underlying cause.
In this patient, actinomycosis was the trigger. Actinomyces are gram-positive, filamentous, commensal bacteria normally found in the human gastrointestinal tract. Actinomyces infection generally occurs in immunosuppressed patients or when the integrity of the gastrointestinal mucosal layer is compromised.
Conclusion: Inflammatory pseudotumor represents a diagnostic conundrum, because its clinical features can be consistent with cancer, infectious disease, or primary immunologic disease. No radiologic or laboratory tests are specific for this condition. This case highlights the diagnostic importance of biopsy and cultures in patients who present with fever and unexplained lymphadenopathy
This post is so scary. The strength of bacteria are astounding. We encounter bacteria so often that it is alarming to see what some can cause. I also found it amazing that with a quick change in medication she was asymptomatic and on the course to complete recovery. This indicates just how important it is to find the exact bacterial culprit in some cases.
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