This article presents a case of a painless fluctuant mass on the volar
aspect of the wrist and forearm of an immunocompetent 45-year-old man with no
history of significant underlying disease. This mass proved to be a chronic
tenosynovitis associated with Mycobacterium kansasii infection. The
patient, who had a history of multiple minor cuts and abrasions plus exposure
to an aquatic environment, had a wide resection of the lesion and elective
tenosynovectomy. Operative findings revealed a marked tenosynovitis of flexor
tendons. Several rice bodies lesions were also observed along the course of the
involved flexor tendons.
Biopsy showed a granulomatous inflammatory reaction. Specimens of
affected tissue were sent to a laboratory for solid (at 30°C and at
37°C) and liquid (at 37°C) mycobacterial culture. The initial
Ziehl-Neelsen stain for acid-fast bacilli was positive. After 8 days of
incubation, acid-fast bacilli were recovered. In accordance with the diagnosis
of M kansasii tenosynovitis and the results of antibiotic susceptibility
testing, triple therapy with rifampicin, isoniazid and clarithromycin was
initiated. After 3 months of therapy, the patient experienced improvement in
the swelling and is due to receive a total of 12 months of antibiotic therapy.
Despite awareness of atypical mycobacterial infections, diagnosis is frequently
delayed, leading to increased morbidity. Patients with exposure to these
atypical pathogens require a broadened differential to include appropriate
testing and culture of specimens to obtain an accurate diagnosis.
Chronic tenosynovitis caused by nontuberculous mycobacteria is
uncommon in clinical practices. The most common reported species are
Mycobacterium marinum and Mycobacterium kansasii, whereas there
are reported cases with other species such as Mycobacterium avium
complex, Mycobacterium malmoense, Mycobacterium szulgai,
Mycobacterium abscessus, Mycobacterium xenopi, and
The etiology remains unclear; however, the disease appears to be
related to previous trauma, contamination during previous surgical procedures,
local corticosteroid injections, or environmental factors (prolonged exposure
to water or soil). Immunosuppression is sometimes associated with these
infections and can be considered as a risk factor.2 Bernard et
al4 described a retrospective study of 10 patients in France and a
review of 40 previously published cases that had M kansasii septic
arthritis. Twenty-six out of 50 patients had no underlying disease.4
One disease characteristic is that most cases are delayed in diagnosis.
This article presents a case of a painless fluctuant mass on the volar
aspect of the wrist and forearm of a 45-year-old man, which was misdiagnosed
and left untreated for 3 years and proved to be a chronic tenosynovitis
associated with M kansasii infection.
A mariner with no significant underlying disease presented with
painless swelling of his left wrist and forearm.
There was no fever, or numbness of the hand, wrist, or forearm. He had
a history of multiple minor cuts and abrasions, plus exposure to an aquatic
environment due to his occupation. His past history was uneventful and he had
no other relevant reports. He was taking no medications and had no history of
allergies, smoking, alcohol, or illicit drug use. A review of systems was
Over 3-year period, he had been treated with multiple aspirations of a
gel-like fluid and had received several regimens of nonsteroidal
antiinflammatory drugs, but had never been treated by steroid injection.
Clinical examination showed a nontender fluctuant swelling over the
palmar aspect of the wrist and forearm and some swelling of the hypothenar
eminence (Figure 1).
Laboratory peripheral blood studies showed that complete blood count
was within normal range, erythrocyte sedimentation rate was 5 mm/hr, and
C-reactive protein was negative. Tuberculin skin testing gave positive results
at 19 mm of induration. Liver enzymes and kidney function were normal. Human
immunodeficiency virus status, rheumatoid factor, and antinuclear antibodies
|Figure 1: Fluctuant
swelling over the palmar aspect of the wrist, forearm, and hypothenar eminence.
There were no granulomas or infiltrates on chest radiograph.
Radiography of the hand, wrist, and forearm showed extensive soft tissue
swelling, whereas magnetic resonance imaging (MRI) revealed marked
tenosynovitis of the flexor tendons.
An elective surgical operation for tenosynovectomy was performed.
Operative findings revealed a marked tenosynovitis of the flexor tendons.
Several rice bodies were observed along the course of the involved flexor
Biopsy showed a granulomatous inflammation reaction, and due to
clinical suspicion of atypical mycobacterial infection, specimens of affected
tissue were sent to a laboratory for mycobacterial culture, as this is the most
sensitive way of diagnosing an atypical mycobacteria infection.5
The specimens proceeded according to standard procedures. Two
Lowenstein-Jensen slants were used for solid cultures (1 at 30°C and 1 at
37°C) and the MGIT960 automated system (Becton Dickinson, Franklin Lakes,
New Jersey) was used for liquid culture at 37°C. The initial Ziehl-Neelsen
stain for acid-fast bacilli was positive. After 8 days of incubation, acid-fast
bacilli were recovered in the MGIT960 system (Figure 2).
| Figure 2:
Microphotography of the M kansasii grown in the MGIT960 liquid medium
After 17 and 19 days of incubation, acid-fast bacilli were
recovered from the Lowenstein-Jensen slants at 30°C and 37°C
respectively. The recovered mycobacterium was identified as M kansasii
by the combined use of the commercial kits Genotype Mycobacterium CM and AS
(Hain, Lifescience, Nehren, Germany) according to the manufacturer’s
instructions (Figure 3).
Microphotography of the M kansasii as shown in the specimen after
aspiration and the white cells. (manipulation, 2400X).
For confirmation of identification of this strain, a 439-bp
fragment of the 65-kDa heat shock protein (hsp65) gene was amplified using the
protocol and the primers Tb11 and TB12 as previously described. The sequence
was compared to other published mycobacterial sequences in the GenBank
database. It showed 100% similarity (346/346 identities) with the hsp65
sequence of M kansasii strain ATCC 12478. The hsp65 gene sequence had
been deposited in GenBank with accession number HM450377 (Figure 4).
Microphotography of the M kansasii as shown after decontamination of the
specimen (manipulation, 1200X).
Susceptibility testing of M kansasii was performed by a
modified microdilution method using the commercially available microplates
Sensititre SLOMYCOI (Trek Diagnostic Systems, Cleveland, Ohio) according to the
manufacturer’s instructions. The antibiotics tested and the minimum
inhibiting concentrations obtained (in parentheses) were: amikacin (64
µg/mL), ciprofloxacin (>16 µg/mL), clarithromycin (1
µg/mL), ethambutol (16 µg/mL), ethionamide (0.3 µg/mL),
isoniazid (1 µg/ml), linezolid (4 µg/mL), moxifloxacin (4
µg/mL), rifampin (0.5 µg/mL), rifabutin (<0.25
µg/mL), and streptomycin (64 µg/mL).6 The strain was
susceptible to clarithromycin, rifampin, rifabutin, and isoniazid, and
resistant to ethambutol, amikacin, ciprofloxacin, and streptomycin.
In accordance with the diagnosis of M kansasii tenosynovitis
and the results of antibiotic susceptibility testing, a triple therapy with
rifampicin, isoniazid, and clarithromycin was initiated. After 3 months of
therapy, the patient experienced improvement in the swelling and is due to
receive a total of 12 months of antibiotic therapy.
This article presented a case of a 45-year-old man with chronic
tenosynovitis of his left forearm and wrist, which was shown to be associated
with M kansasii infection. However, chronic tenosynovitides are not
uncommon; one should always suspect rare causative factors such as
Mycobacterium tuberculosis, fungi infections (including Histoplasma
capsulatum and Sporothrix schenkii) and nontuberculous mycobacteria,
with M kansasii being among the most commonly reported
Patients with chronic tenosynovitis may present with carpal tunnel
syndrome. A tendon rupture is a rare complication, however it may occur when
the corrected diagnosis and appropriate treatment are delayed. Erythrocyte
sedimentation rate and C-reactive protein are normal in most patients. Magnetic
resonance imaging is useful for a diagnosis characterized by a marked synovial
thickening around the flexor tendons.
A correct diagnosis is usually made late in the course of illness,
typically >6 months.7 Rice-body formation can be noted in
patients with nontuberculous mycobacteria chronic tenosynovitis, as in our
patient. In our patient, it took 3 years to make the definite diagnosis of M
kansasii tenosynovitis. A delayed diagnosis of nontuberculous Mycobacteria
tenosynovitis is problematic and attributable to a lack of clinical suspicion.
Biopsy tissues with staining of acid-fast bacilli, cultures for Mycobacterium
using Lowenstein-Jensen with a long incubation of more than 12 weeks, and using
2 temperatures of 30°C and 37°C are the keys for identification of
Mycobacterium species. Our patient’s antimycobacterial regimen will be
isoniazid, rifampicin, and clarithromycin for 1 year.4 Given the
fact that the patient had a surgical intervention that directly decreased the
bacterial burden, the course of antimycobacterial regimen may be adequate.
Another problem regarding therapeutic issue is the duration of medical
treatment for this organism. M kansasii is a relatively drug-resistant
organism, compared to M tuberculosis. However, a specific medical
treatment often results in an excellent clinical response but no known exact
time to discontinue the drugs.3 Apart from medical treatment, many
reports regarded the surgical intervention as an arbitrary choice of treatment
of M kansasii tenosynovitis. Although most reports recommended the
surgical treatment of this entity, the indication for surgery is usually due to
the worsening symptoms of patients. A previous study described a case of M
kansasii tendinitis and fasciitis was successfully treated with only
antimycobacterial agents for 2 years.8
The combined medical and surgical approach resulted in a positive
outcome. Despite awareness of atypical mycobacterial infections, diagnosis is
frequently delayed, leading to increased morbidity. Patients with an exposure
to these atypical pathogens require a broadened differential to include
appropriate testing and appropriate culture of specimens to obtain an accurate
- Leader M, Revell P, Clarke G. Synovial infection with
Mycobacterium kansasii. Ann Rheum Dis. 1984; 43(1):80-82.
- Tangkosakul T, Hongmanee P, Santanirand P, et al. Tenosynovitis
caused by mycobacterium kansasii: a case report and literature review.
J Infect Dis Antimicrob Agents. 2007; 24(3):143-148.
- Kang GC, Gan AW, Yam A, Tan AB, Tay SC. Mycobacterium abscessus
hand infections in immunocompetent fish handlers: case report. J Hand Surg
Am. 2010; 35(7):1142-1145.
- Bernard L, Vincent V, Lortholary O, et al. Mycobacterium
kansasii septic arthritis: French retrospective study of 5 years and
review. Clin Infect Dis. 1999; 29(6):1455-1460.
- Lorenz HM, Dalpke AH, Deboben A, et al. Mycobacterium
kansasii tenosynovitis in a rheumatoid arthritis patient with long-term
therapeutic immunosuppression. Arthritis Rheum. 2008; 59(6):900-903.
- da Silva Telles MA, Chimara E, Ferrazoli L, Riley LW.
Mycobacterium kansasii: antibiotic susceptibility and PCR-restriction
analysis of clinical isolates. J Med Microbiol. 2005; 54(Pt
- Lidar M, Elkayam O, Goodwin D, et al. Protracted Mycobacterium
kansasii carpal tunnel syndrome and tenosynovitis. Isr Med Assoc J.
- Parker MD, Irwin RS. Mycobacterium kansasii tendinitis and
fasciitis. Report of a case treated successfully with drug therapy alone. J
Bone Joint Surg Am. 1975; 57(4):557-559.
Drs Mazis and Sakellariou are from the First Department of Orthopedic
Surgery and Drs Kontos and Zerva are from the Clinical Microbiology Laboratory,
University of Athens, Medical School, ATTIKON University General Hospital,
Chaidari, and Dr Spyridonos is from the Department of Hand Surgery, Upper Limb,
and Microsurgery, KAT General Hospital, Kifissia, Greece.
Drs Mazis, Sakellariou, Kontos, Zerva, and Spyridonos have no relevant
financial relationships to disclose.
Correspondence should be addressed to: George A. Mazis, MD, MSc, First
Department of Orthopedic Surgery, University of Athens, Medical School, ATTIKON
University General Hospital, 1 Rimini St, 12462, Chaidari, Greece