A seventeen-year-old boy presented to our clinic with a chief complaint of an insidious onset of hip pain of approximately two weeks’ duration that was minimally responsive to nonsteroidal anti-inflammatory drugs. He had previously worked at a job in construction requiring heavy labor and lived in the Missouri River valley region. The hip pain was limiting his ability to work at his normal level. The pain was primarily localized to the lateral aspect of the hip at the greater trochanteric region and the lateral iliac wing without radiation. He denied any fevers, chills, or other constitutional symptoms at that time. Incidentally, he was concurrently being treated for acute renal colic following passage of a renal colliculus two weeks previously.
On physical examination, the patient had no pain with a full range of motion of the hip. He had mild tenderness to palpation over the proximal portion of the iliotibial band and greater trochanter. No erythema or draining sinus was present. He had normal findings on a neurovascular examination. An initial provisional diagnosis of iliotibial band syndrome was made, and management consisted of rest, cryotherapy, iliotibial band stretching exercises, and the use of nonsteroidal anti-inflammatory medications. Radiographs made during this initial clinic visit revealed no acute osseous injury, but they did show an ill-defined lytic lesion of the right ilium (Fig. 1).
Concurrently, a renal ultrasound evaluation revealed a 2.0 × 1.9 × 3.1-cm hypoechoic irregular avascular area within the superior pole of the left kidney. A computed tomography scan of the abdomen demonstrated a 4.8 × 3.1 × 9.5-cm mass involving the left kidney, the psoas muscle, and the crus of the diaphragm. Additionally, a 3.7 × 1.3 × 1.5-cm lytic lesion of the right ilium with ill-defined margins and adjacent periosteal reaction was evident (Fig. 2).
Serum markers of inflammation were an erythrocyte sedimentation rate of 72 mm/hr (normal, <15 mm/hr) and a C-reactive protein level of 27.6 mg/dL (normal, <0.9 mg/dL). In cooperation with the renal service, a magnetic resonance imaging scan of the abdomen and pelvis was acquired (Fig. 3). Multiple lytic lesions were noted within the ischium, both femoral necks, and both ilia. The largest lesion of the right ilium extended into the iliacus and gluteal musculature. A computed tomography-guided biopsy of the right gluteal muscle mass and iliac bone revealed blastomycosis, with broad-based budding yeast. Cultures grew Blastomyces dermatitidis, which was confirmed with a DNA probe. The lesions within the kidney, pelvis, femora, and surrounding musculature were believed to be manifestations of disseminated blastomycosis.
The infectious disease service was consulted, and a workup for immunodeficiency was negative. Additional history revealed that the patient had several prior summertime jobs involving excavation and demolition work. The patient was also heavily involved with turf and landscape management classes at school. He was treated with oral itraconazole.
The pain continued to increase gradually, and he required intermittent narcotic pain medication. He had no restrictions of weight-bearing, but at times he used crutches because of the pain. After approximately one month of therapy, the C-reactive protein level and erythrocyte sedimentation rate had decreased to 0.5 mg/dL and 31 mm/hr, respectively. Itraconazole therapy was continued for one year. At a follow-up examination, a computed tomography scan revealed a decrease in the size of the lesions and the development of sclerotic-appearing bone within them (Fig. 4). At one year after presentation, the patient was back to his normal routine and was able to work without limitations at a full-time construction job where he performed heavy labor. The pain was markedly decreased, and he had no complaints. At the time of the last clinical evaluation, the patient had remained asymptomatic and the erythrocyte sedimentation rate and C-reactive protein levels were within normal limits.
Blastomyces dermatitidis is a thermally dimorphic fungus that exists in the mycelial form at room temperature and converts to a yeast phase at body temperature. It is endemic within North America in the south central and southeastern states that border the Mississippi and Ohio River valleys4. While blastomycosis initially may be introduced by means of the respiratory system, it can present with extrapulmonary manifestations. Inhalation of the fungal spores, or conidia, into the lungs results in pulmonary infection when the conidia escape natural defenses and are converted into the yeast form, which is more resistant to phagocytosis and killing4. The yeast form may then spread hematogenously to almost any location in the body5.
Blastomycosis can involve all bones, and osseous manifestations have been estimated to occur in 15% to 60% of cases5. After lung and skin involvement, bone is the third most common site of blastomycotic lesions. The most common sites of osseous involvement are the lower limb and axial skeleton. In a retrospective review of forty-five patients, clinical presentation of disseminated blastomycosis included common orthopaedic symptoms such as pain (78%), swelling (59%), and soft-tissue abscess (39%)6.
The treatment of blastomycosis is varied and dependent on the presentation of the disease. Untreated blastomycosis has been associated with mortality rates approaching 60%, and spontaneous resolution of chronic blastomycosis is rare. Therefore, it is recommended that all patients with chronic pulmonary or extrapulmonary blastomycosis be treated with antifungal therapy. Oral antifungal therapy with itraconazole or ketoconazole for at least six months is the current recommendation for patients without life-threatening disease or central nervous system involvement4.
In our patient, a multidisciplinary approach facilitated the diagnosis of this unusual problem. The patient presented with many symptoms, and a unifying diagnosis was not found until the tissue diagnosis of a fungal infection was made. Although the definitive diagnosis was not high on the initial differential diagnosis for this patient, infectious causes should be considered in the workup of patients who present with common signs and symptoms but do not respond to initial nonoperative treatment.