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Periprosthetic mycobacterial infection CT and mammographic findings
ELSEVIER
PERIPROSTHETIC MYCOBACI’ERIAL INFEtX.ION CT AND MAMMOGRAPHIC FINDINGS RUTH WALSH, MD, MARK A. KLIEWER, MD, DANIEL C. SULLIVAN, MD, BARBARA HERTZBERG, ERIK K. PAULSON, MD, MARY SCOTT SOO, MD, FAYSAL A. SAKSOUK, MD, AND PHYLLIS J. KORNGUTH, MD, PHD Organisms of the Mycobacterium fortuitum complex are an uncommon but important cause of periprosthetic infection following augmentation mammoplasty or other breast surgery This etiological agent must be considered in the particular case ofperiprosthetic infection, because special handling of the fluid is crucial to enhance recovery of the organism. We describe the computed tomography (CT) and mammographic findings in such an abscess with respect to the clinical context and subsequent management. To our knowledge, CT findings associated with any periprosthetic breast infection have not been described. KEY WORDS:
prosthesis; Computed tomography;Breast; Infection, atypical; Mycobacterium
Mammary
MD,
wound infections and soft-tissue abscesses following surgery and trauma elsewhere in the body. Because these organisms are only rarely the cause of infection in the breast, diagnosis and initiation of appropriate treatment are frequently delayed. Over a Xi-year period, the clinical findings of 17 periprostbetic infections due to M. fortuitum complex were reported by Clegg et al. from the Centers for Disease Control (1, 2). Imaging studies are increasingly utilized to evaluate suspected breast prosthesis complications, yet the imaging findings in patients with periprosthetic M. fortuitum complex infection have not, to our knowledge, been previously described (3). We present the mammographic and computed tomography (CT) findings of a periprostbetic infection due to M. fortuitum and discuss the consequent diagnostic and therapeutic implications.
INTRODUCXION
CASE REPORT
Periprostbetic infection is a rare but serious complication of breast implant surgery. If unrecognized and unchecked, infection can lead to wound dehiscence, loss of the prosthesis, or disfiguring scar tissue formation. Though Staphylococcus aureus is the most common agent, other potential pathogens must be considered. Organisms of the Mycobacterium fortuitum complex (rapidly growing strains including M. fortuiturn and M. chelonei) are well-recognized causes of
A &year-old woman underwent bilateral simple mastectomy and submuscular placement of tissue expanders for lobular carcinoma in situ and multifocal atypical lobular hyperplasia. After tissue expansion was complete, silicone breast prostheses were placed bilaterally and the nipple-areolar complexes were reconstructed. Approximately 6 weeks following placement of the prostheses, fever, chills, and myalgia developed. Four days later, swelling and tenderness of the left breast developed; the white blood cell count was normal. Mammography demonstrated bilateral silicone implants with no evidence of extracapsular rupture. Views of the left breast showed subtle skin thickening and increased density of the subcutaneous tissues as compared with the right breast (Figure 1) but a more com-
From the Departmentof Radiology,DukeUniversityMedical Center, Durham, North Carolina. Address reprint requests to: Ruth Walsh, MD, Duke University Medical Center, Department of Radiology, I?O. Box 3808, Durham, NC 27710. Received June 1, 1994; accepted July 6, 1994. CLINICAL IMAGING1995;19:193-196 Q Elsevier Science Inc., 1995 655 Avenue of the Americas, New York, NY 10010
0899-7071/95/$9.50 SSDI 0899-7071(94)00048-H
CLINICAL IMAGING VOL. 19, NO. 3
FIGURE 2. This contrast-enhanced Cl’ image obtained through the inferior aspect of the prosthesis [small arrowbeads) demonstrates a peripmsthetic fluid collection (f) with a thick enhancing ill-defined rim. Increased density is present in the subcutaneous fat (arrow), as was evident by mammography.
(A) Mammogram of the left breast. The mediolateral oblique view demonstrates the submuscular implant and a subtle increased density in the subcutaneous fat [arrows) as compared with the right breast. (B) The mammogram of the right breast demonstrates a submuscular singlelumen silicone prosthesis with a small amount of overlying subcutaneous tissue and skin. FIGURE 1.
plete mammographic examination of the soft tissues of the breast was precluded hy the marked tenderness of the area. Because the prosthesis and posterior portion of the left breast could not be adequately evaluated hy mammography, contrast-enhanced CT was performed. The right breast implant appeared normal. CT corroborated the mammographic findings of skin thickening and increased density in the subcutaneous fat in the left breast, but in addition showed a large submuscular low-attenuation fluid collection adjacent to the prosthesis and deforming its contour (Figure 2). This finding was not appreciated hy mammography. The silicone gel prosthesis was of higher attenuation than the surrounding fluid collection and had a homogeneous appearance (4). Both the prosthesis and fluid collection were surrounded by a contrast-enhancing rim [Figure 3). Subsequent surgical exploration produced a copious amount of straw-colored fluid which was drained, and the prosthesis was removed. Cultures grew M. fortuitum. The patient was treated for 6 months with a
three-drug regimen of amikacin, sulfisoxazole, and ciprofloxacin. Eight months later, the submuscular pocket was recreated and a tissue expander placed. The expander was left in place for 3 years with no evidence of recurrent infection and was finally replaced with a permanent saline prosthesis. No further complications occurred.
DISCUSSION Infection associated with silicone breast prostheses is remarkably uncommon considering the potentially nonsterile environment of the surrounding breast. Not
FIGURE 3. Contrast-enhanced CT through the thorax at the midlevel of the breast. The submuscular silicone prosthesis in the left breast [small armwheads) is surrounded by a large fluid collection (f) with a contrast-enhancing rim [arrows).
JULY-SEPTEMBER
1995
only is the endogenous flora of the breast ducts similar to that of the skin, but also these ducts are known to connect with the periprosthetic space in some cases (5). Even so, the infection rate typically ranges between 1 and 4% after augmentation mammoplasty (2) and 2 to 6% after breast reconstruction (5). Overall, mycobacterial infections contribute little to these rates, but clusters of these infections have been observed (1, 2). The median incubation period for infection with M. fofiuitum complex is 28 days after surgery, but the onset of infection can vary from 1 week to over 2 years. The source of the infection is unclear, but in view of the temporally and geographically related clusters of infections, it is probable that the organism is transiently present in an unidentified environmental source in the operating room. Indeed, M. fortuitum has a wide environmental distribution and has been recovered from soil, water, operating room scrub sinks, and dust (1, 5, 6). Local signs of infection without systemic illness are the clinical hallmark of periprosthetic mycobacterial infections (1, 7). Breast swelling, tenderness, erythema at the incision or overlying the prosthesis, calor, and discharge of fluid or extrusion of the prosthesis through the incision site have been reported (1). On surgical exploration the periprosthetic fluid is usually clear to cloudy, odorless (7), and localized in the periprosthetic space (1). Mammography and sonography have been used for evaluating complications following augmentation mammoplasty. These complementary methods of imaging are useful in evaluating implant rupture, periprosthetic hematomas, and fluid collections including abscesses (3). As a rule, dedicated CT mammography has had a limited role in the evaluation of breast disease because of the increased radiation dose, increased cost, spatial resolution limitations, and risk of contrast media reaction (8). However,CT can be helpful as a problem-solving tool in certain circumstances. In the present case, CT revealed the extent and character of the fluid collection and allowed easy comparison with the normal implant on the other side. While ultrasonography may have provided similar information, it was not performed in our patient because it is known to be of limited value in examining the posterior aspect of the prosthesis and subjacent chest wall. In addition to infection, a postoperative seroma/hematoma and a double-lumen prosthesis would need to be considered in the differential diagnosis for this CT appearance. The surgical history excluded a doublelumen implant in this patient. Also, the wall of the inflatable (saline-filled) outer compartment of a doublelumen implant is thin, whereas in this case the enhancing rim was thick and ill-defined (9). In view of the
PERIPROSTHETIC
MYCOBACTERIAL
INFECTION
195
patient’s clinical symptoms and time course of the development of the fluid collection, a periprosthetic infection was favored over postoperative seroma. Though it seems unlikely that the imaging findings are specific for atypical mycobacteria, the recognition that atypical mycobacterial infection is a serious consideration is fundamental to successful diagnosis and treatment. As illustrated in this case, mammography in patients with periprosthetic infections may be unduly painful and unable to identify significant periprosthetic fluid collections, so ultrasonography or CT should be considered. Infection by M. fortuitum complex should be suspected if a large peri-implant fluid collection with enhancing rim is identified by imaging studies after a long latent period following implantation surgery, and the specimen should be handled accordingly (1, 7). Both a Gram stain and an acid-fast smear need to be performed. Routine cultures should undergo prolonged incubation and mycobacteria culture media should be inoculated to enhance recovery of the organism (1,2). However, even with appropriate diagnosis, removal of the prosthesis, and antimicrobial therapy, the organism can persist in the breast for months and recur after reimplantation (1). Careful surveillance is essential following reimplantation to detect recurrence of the infection. The imaging findings of periprosthetic breast infections have received surprisingly little attention in the radiological literature. Indeed, the CT findings associated with any periprosthetic breast infection, regardless of the pathological agent, have not been described to our knowledge. We stress the importance of considering infection, including an atypical infection such as M. fortuitum complex, in addition to postoperative seroma/hematoma and double-lumen implant (9) when a low-attenuation fluid collection is identified surrounding a breast implant.
REFERENCES 1. Clegg HW, Foster MT, Sanders WE, et al. Infection due to organ-
isms of the Mycobacterium fortuitum complex after augmentation mammoplasty: clinical and epidemiologic features. J Infect Dis 1983;147:427-433. 2. Clegg HW, Bertagnoll P, Hightower AW, et al. Mammoplastyassociated mycobacterial infection: a survey of plastic surgeons. Plast Reconstr Surg 1983;72:165-169. 3. Van Wingerden JJ, van Staden MM. Ultrasound mammography in prostheses-related breast augmentation complications. Ann Plast Surg 1989;22:32-35. 4. Scott IR, Mueller NL, Fitzpatrick DG, et al. Ruptured breast implant: computed tomographic and mammogmphic findings. Can Assoc Radio1 J 1988;39:152-154. 5. Freedman AM, Jackson IT. Infections in breast implants. Infect Dis Clin North Am 1989;3:275-287.
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WALSH ET AL.
6. Wallace RJ, Steele IX, Labidi A, Silcox VA. Heterogeneity among isolates of rapidly growing mycobacteria responsible for infection following augmentation msmmoplasty despite case clustering in ‘l&as and other southern coastal states. J Infect Dis 1989; 160:281-288. 7. Toranto IR, Malow JB. Atypical mycobacterial
periprosthetic
in-
fections: diagnosis and treatment. 226-226.
Plast Reconstr Surg 1960;66:
8. Wechsler RJ. Evaluating breast cancer: use of cross-sectional aging. Radio1 Report 1989;1:180-187.
im-
9. O’Mara EM, Rmnes DR, Argenta LC. Combination gel-inflatable mammary prosthesis: appearance at CT. Radiology 1989;170:78.
PERIPROSTHETIC MYCOBACI’ERIAL INFEtX.ION CT AND MAMMOGRAPHIC FINDINGS RUTH WALSH, MD, MARK A. KLIEWER, MD, DANIEL C. SULLIVAN, MD, BARBARA HERTZBERG, ERIK K. PAULSON, MD, MARY SCOTT SOO, MD, FAYSAL A. SAKSOUK, MD, AND PHYLLIS J. KORNGUTH, MD, PHD Organisms of the Mycobacterium fortuitum complex are an uncommon but important cause of periprosthetic infection following augmentation mammoplasty or other breast surgery This etiological agent must be considered in the particular case ofperiprosthetic infection, because special handling of the fluid is crucial to enhance recovery of the organism. We describe the computed tomography (CT) and mammographic findings in such an abscess with respect to the clinical context and subsequent management. To our knowledge, CT findings associated with any periprosthetic breast infection have not been described. KEY WORDS:
prosthesis; Computed tomography;Breast; Infection, atypical; Mycobacterium
Mammary
MD,
wound infections and soft-tissue abscesses following surgery and trauma elsewhere in the body. Because these organisms are only rarely the cause of infection in the breast, diagnosis and initiation of appropriate treatment are frequently delayed. Over a Xi-year period, the clinical findings of 17 periprostbetic infections due to M. fortuitum complex were reported by Clegg et al. from the Centers for Disease Control (1, 2). Imaging studies are increasingly utilized to evaluate suspected breast prosthesis complications, yet the imaging findings in patients with periprosthetic M. fortuitum complex infection have not, to our knowledge, been previously described (3). We present the mammographic and computed tomography (CT) findings of a periprostbetic infection due to M. fortuitum and discuss the consequent diagnostic and therapeutic implications.
INTRODUCXION
CASE REPORT
Periprostbetic infection is a rare but serious complication of breast implant surgery. If unrecognized and unchecked, infection can lead to wound dehiscence, loss of the prosthesis, or disfiguring scar tissue formation. Though Staphylococcus aureus is the most common agent, other potential pathogens must be considered. Organisms of the Mycobacterium fortuitum complex (rapidly growing strains including M. fortuiturn and M. chelonei) are well-recognized causes of
A &year-old woman underwent bilateral simple mastectomy and submuscular placement of tissue expanders for lobular carcinoma in situ and multifocal atypical lobular hyperplasia. After tissue expansion was complete, silicone breast prostheses were placed bilaterally and the nipple-areolar complexes were reconstructed. Approximately 6 weeks following placement of the prostheses, fever, chills, and myalgia developed. Four days later, swelling and tenderness of the left breast developed; the white blood cell count was normal. Mammography demonstrated bilateral silicone implants with no evidence of extracapsular rupture. Views of the left breast showed subtle skin thickening and increased density of the subcutaneous tissues as compared with the right breast (Figure 1) but a more com-
From the Departmentof Radiology,DukeUniversityMedical Center, Durham, North Carolina. Address reprint requests to: Ruth Walsh, MD, Duke University Medical Center, Department of Radiology, I?O. Box 3808, Durham, NC 27710. Received June 1, 1994; accepted July 6, 1994. CLINICAL IMAGING1995;19:193-196 Q Elsevier Science Inc., 1995 655 Avenue of the Americas, New York, NY 10010
0899-7071/95/$9.50 SSDI 0899-7071(94)00048-H
CLINICAL IMAGING VOL. 19, NO. 3
FIGURE 2. This contrast-enhanced Cl’ image obtained through the inferior aspect of the prosthesis [small arrowbeads) demonstrates a peripmsthetic fluid collection (f) with a thick enhancing ill-defined rim. Increased density is present in the subcutaneous fat (arrow), as was evident by mammography.
(A) Mammogram of the left breast. The mediolateral oblique view demonstrates the submuscular implant and a subtle increased density in the subcutaneous fat [arrows) as compared with the right breast. (B) The mammogram of the right breast demonstrates a submuscular singlelumen silicone prosthesis with a small amount of overlying subcutaneous tissue and skin. FIGURE 1.
plete mammographic examination of the soft tissues of the breast was precluded hy the marked tenderness of the area. Because the prosthesis and posterior portion of the left breast could not be adequately evaluated hy mammography, contrast-enhanced CT was performed. The right breast implant appeared normal. CT corroborated the mammographic findings of skin thickening and increased density in the subcutaneous fat in the left breast, but in addition showed a large submuscular low-attenuation fluid collection adjacent to the prosthesis and deforming its contour (Figure 2). This finding was not appreciated hy mammography. The silicone gel prosthesis was of higher attenuation than the surrounding fluid collection and had a homogeneous appearance (4). Both the prosthesis and fluid collection were surrounded by a contrast-enhancing rim [Figure 3). Subsequent surgical exploration produced a copious amount of straw-colored fluid which was drained, and the prosthesis was removed. Cultures grew M. fortuitum. The patient was treated for 6 months with a
three-drug regimen of amikacin, sulfisoxazole, and ciprofloxacin. Eight months later, the submuscular pocket was recreated and a tissue expander placed. The expander was left in place for 3 years with no evidence of recurrent infection and was finally replaced with a permanent saline prosthesis. No further complications occurred.
DISCUSSION Infection associated with silicone breast prostheses is remarkably uncommon considering the potentially nonsterile environment of the surrounding breast. Not
FIGURE 3. Contrast-enhanced CT through the thorax at the midlevel of the breast. The submuscular silicone prosthesis in the left breast [small armwheads) is surrounded by a large fluid collection (f) with a contrast-enhancing rim [arrows).
JULY-SEPTEMBER
1995
only is the endogenous flora of the breast ducts similar to that of the skin, but also these ducts are known to connect with the periprosthetic space in some cases (5). Even so, the infection rate typically ranges between 1 and 4% after augmentation mammoplasty (2) and 2 to 6% after breast reconstruction (5). Overall, mycobacterial infections contribute little to these rates, but clusters of these infections have been observed (1, 2). The median incubation period for infection with M. fofiuitum complex is 28 days after surgery, but the onset of infection can vary from 1 week to over 2 years. The source of the infection is unclear, but in view of the temporally and geographically related clusters of infections, it is probable that the organism is transiently present in an unidentified environmental source in the operating room. Indeed, M. fortuitum has a wide environmental distribution and has been recovered from soil, water, operating room scrub sinks, and dust (1, 5, 6). Local signs of infection without systemic illness are the clinical hallmark of periprosthetic mycobacterial infections (1, 7). Breast swelling, tenderness, erythema at the incision or overlying the prosthesis, calor, and discharge of fluid or extrusion of the prosthesis through the incision site have been reported (1). On surgical exploration the periprosthetic fluid is usually clear to cloudy, odorless (7), and localized in the periprosthetic space (1). Mammography and sonography have been used for evaluating complications following augmentation mammoplasty. These complementary methods of imaging are useful in evaluating implant rupture, periprosthetic hematomas, and fluid collections including abscesses (3). As a rule, dedicated CT mammography has had a limited role in the evaluation of breast disease because of the increased radiation dose, increased cost, spatial resolution limitations, and risk of contrast media reaction (8). However,CT can be helpful as a problem-solving tool in certain circumstances. In the present case, CT revealed the extent and character of the fluid collection and allowed easy comparison with the normal implant on the other side. While ultrasonography may have provided similar information, it was not performed in our patient because it is known to be of limited value in examining the posterior aspect of the prosthesis and subjacent chest wall. In addition to infection, a postoperative seroma/hematoma and a double-lumen prosthesis would need to be considered in the differential diagnosis for this CT appearance. The surgical history excluded a doublelumen implant in this patient. Also, the wall of the inflatable (saline-filled) outer compartment of a doublelumen implant is thin, whereas in this case the enhancing rim was thick and ill-defined (9). In view of the
PERIPROSTHETIC
MYCOBACTERIAL
INFECTION
195
patient’s clinical symptoms and time course of the development of the fluid collection, a periprosthetic infection was favored over postoperative seroma. Though it seems unlikely that the imaging findings are specific for atypical mycobacteria, the recognition that atypical mycobacterial infection is a serious consideration is fundamental to successful diagnosis and treatment. As illustrated in this case, mammography in patients with periprosthetic infections may be unduly painful and unable to identify significant periprosthetic fluid collections, so ultrasonography or CT should be considered. Infection by M. fortuitum complex should be suspected if a large peri-implant fluid collection with enhancing rim is identified by imaging studies after a long latent period following implantation surgery, and the specimen should be handled accordingly (1, 7). Both a Gram stain and an acid-fast smear need to be performed. Routine cultures should undergo prolonged incubation and mycobacteria culture media should be inoculated to enhance recovery of the organism (1,2). However, even with appropriate diagnosis, removal of the prosthesis, and antimicrobial therapy, the organism can persist in the breast for months and recur after reimplantation (1). Careful surveillance is essential following reimplantation to detect recurrence of the infection. The imaging findings of periprosthetic breast infections have received surprisingly little attention in the radiological literature. Indeed, the CT findings associated with any periprosthetic breast infection, regardless of the pathological agent, have not been described to our knowledge. We stress the importance of considering infection, including an atypical infection such as M. fortuitum complex, in addition to postoperative seroma/hematoma and double-lumen implant (9) when a low-attenuation fluid collection is identified surrounding a breast implant.
REFERENCES 1. Clegg HW, Foster MT, Sanders WE, et al. Infection due to organ-
isms of the Mycobacterium fortuitum complex after augmentation mammoplasty: clinical and epidemiologic features. J Infect Dis 1983;147:427-433. 2. Clegg HW, Bertagnoll P, Hightower AW, et al. Mammoplastyassociated mycobacterial infection: a survey of plastic surgeons. Plast Reconstr Surg 1983;72:165-169. 3. Van Wingerden JJ, van Staden MM. Ultrasound mammography in prostheses-related breast augmentation complications. Ann Plast Surg 1989;22:32-35. 4. Scott IR, Mueller NL, Fitzpatrick DG, et al. Ruptured breast implant: computed tomographic and mammogmphic findings. Can Assoc Radio1 J 1988;39:152-154. 5. Freedman AM, Jackson IT. Infections in breast implants. Infect Dis Clin North Am 1989;3:275-287.
196
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WALSH ET AL.
6. Wallace RJ, Steele IX, Labidi A, Silcox VA. Heterogeneity among isolates of rapidly growing mycobacteria responsible for infection following augmentation msmmoplasty despite case clustering in ‘l&as and other southern coastal states. J Infect Dis 1989; 160:281-288. 7. Toranto IR, Malow JB. Atypical mycobacterial
periprosthetic
in-
fections: diagnosis and treatment. 226-226.
Plast Reconstr Surg 1960;66:
8. Wechsler RJ. Evaluating breast cancer: use of cross-sectional aging. Radio1 Report 1989;1:180-187.
im-
9. O’Mara EM, Rmnes DR, Argenta LC. Combination gel-inflatable mammary prosthesis: appearance at CT. Radiology 1989;170:78.