Spleen calcifications have been found in autosplenectomy, thorium dioxide exposure‐related fibrosis, tuberculosis, Pneumocystis carinii infection, and Histoplasma capsulatum infection. 1 Rarely, calcification can also be associated with systemic lupus erythematosus (SLE) of the spleen. 1 Herein, we present a case with a history of SLE, who was subsequently infected with Mycobacterium kansasii and developed diffuse spleen calcifications.
A 69‐year‐old female, with a history of SLE for 12 years, suffered from episodic epigastric pain and chronic cough for 7 years. She felt hunger pain, which radiated to the left shoulder, progressive abdominal fullness in the left hypochondrial region, and a weight loss of 10 kg in the past 1 year. A chest X‐ray revealed the infiltration in the lower lobe of the right lung, while a plain abdominal X‐ray showed diffuse calcification of the spleen (Figure 1(A)). Abdominal computed tomography (CT) showed splenomegaly with microlithiasis, without enlarged lymph nodes (Figure 1(B)). A bronchoscopy did not show any endobronchial lesion. The culture of the bronchial wash over the lower lobe of the right lung yielded no bacterial growth. Other test results, including those of acid fast staining, tuberculosis polymerase chain reaction test, cytology, Cryptococcus antigen, and Aspergillus antigen were negative. However, a mycobacterial culture yielded M. kansasii 1 month later.
FIGURE 1.
(A) Abdominal plain film revealed diffuse spleen calcification. (B) Abdominal computed tomography disclosed diffusely and densely distributed coarse, round, and ovoid spleen calcifications along with microlithiasis in the spleen
She received therapy with rifampicin, ethambutol, and azithromycin. The abdominal pain and cough gradually subsided. A chest X‐ray showed the regression of the lesion in the lower lobe of the right lung, but the follow‐up abdominal CT scan did not show the resolution of splenomegaly and microlithiasis.
The exact pathological mechanisms of spleen calcification have not been identified. This patient received antimycobacterial therapy for 12 months, which had minimum effect on spleen calcification at the follow up abdominal CT scan. This suggests that spleen calcification might be due to SLE‐related perivascular calcification and fibrosis rather than M. kansasii infection. Mycobacterium species that involvement of the liver and spleen is common in patients with disseminated infection. It manifests as diffuse liver or spleen enlargement with multiple hypodense small masses scattered throughout the organ, ranging in size from 1 to 3 cm in CT scan. Early in the evolution of the lesion its is similar to that of an abscess whereas more advanced lesions usually calcify. 2 Our patient had been receiving the abdomen and chest CT annually for following up her thymoma. We did not see any hypodense lesion developed throughout the series of imaging. In contrast to the lupus‐associated splenic calcifications, calcification secondary to Mycobacterium infection is sparing of the outer parenchyma, just deep to the capsule. 2 This relative sparing of the capsule and subcapsular tissue argues against calcification of supporting interstitial connective tissue. The calcified splenic nodules in SLE may represent calcification in the “onion‐skin lesions” described in our patient and previous report. 1
Spleen calcification is a characteristic of connective tissue diseases; but the exact mechanism of diffuse spleen calcification is still unknown. Fc‐receptor blockade by circulating immune complex could lead to functional hyposplenism. 3 These spleen calcifications therefore are apparently visceral vasculitic manifestations in SLE patients with disease activity. 1 The association between high levels of anti‐DNA antibodies and disease activity has been widely appreciated. 4 In our case, SLE activity and spleen calcifications observed in the abdominal CT scan increased simultaneously during 2014–2016.
With increasing SLE activity, immunosuppressants are prescribed to control the disease activity. However, there is a higher incidence of multiple opportunistic infections in SLE patients with increased disease activity controlled with the indicated doses of corticosteroids. Given that pulmonary calcifications were found to remain unchanged or increase in size after complete antituberculosis medication in 17.8% cases, 5 it is significant that spleen calcification did not diminish, although symptoms of cough and abdominal pain improved after antimycobacterial regimens. The fibrosis and scarring occurring in caseating granulomas have been found to be irreversible in a previous histopathologic analysis. 5
The significance of this case is the worsening of spleen calcifications in an SLE patient with increased disease activity after M. kansasii infection.
CONFLICT OF INTEREST
The authors declare no potential conflict of interest.
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