A 53-year-old male with a clinical history of nephrolithiasis came to the outside hospital emergency room (ER) with severe pain in the low back, right hip, and thigh, intermittent fever with chills and night sweats, minimally productive intermittent cough spells with whitish phlegm, exertional dyspnea, generalized fatigue for three weeks along with weight loss of 20 pounds in one month. Six days prior, he was seen at the ER for back pain radiating to the right leg for the last two weeks, and x-rays of the right knee and hip with pelvis were within normal limits. He was discharged home with oral prednisone 40 mg daily for five days and as needed diazepam. He was a farmworker, had quit smoking a month back with 30 pack-years of smoking, and was negative for substance and alcohol abuse. He was sexually active with his girlfriend and resided in a trailer. Clinical examination revealed stable vital signs, lack of sensation over the right anterolateral thigh with no point tenderness, painful hip movements with limited motion, and difficulty walking. Labs revealed leukocytosis, thrombocytosis, hypoalbuminemia, and elevated inflammatory markers (Table 1). He received intravenous (IV) ketorolac 30 milligrams (mg) followed by hydromorphone 0.5 mg 1 dose IV, ondansetron 4 mg IV, and oral diazepam 2 mg. Contrasted computed tomography (CT) of the chest, abdomen, and pelvis revealed right upper lobe (RUL) heterogeneous enhancing mass and scattered bilateral nodules < 6 millimeters (Fig. 1), right iliac diffuse permeative appearance, extensive complex septated acute collections within the right iliopsoas region, deep right gluteal region and the right paraspinal musculature from the L4 - S2 levels. Magnetic resonance imaging (MRI) of the pelvis and lumbar spine with and without contrast revealed a large multilobulated cystic mass centered around the right iliac bone with extension medially into portions of the iliopsoas muscle, laterally into the adjacent gluteal musculature, and posterosuperiorly into the posterior paraspinal musculature (Fig. 2). He was admitted and initiated on pain control, IV fluids, and evaluated by the oncology and orthopedics team, who recommended a biopsy or transfer to a tertiary center. On day two, he was febrile at 39.2 Celsius (C) and ordered blood cultures returned negative, whereas procalcitonin and lactic acid were elevated (Table 1). Empirical IV ceftriaxone and azithromycin were started for suspected right upper lobe pneumonia, and his lactic acid improved. Over the next three days, antibiotics were continued, and on day six, he was transferred to our institution for suspected primary bone malignancy with metastasis.
On arrival, clinical examination revealed fever (39 C), mild improvement of the right hip movements, and poor oral hygiene. Labs revealed leukocytosis, thrombocytosis, and two sets of blood cultures returned negative (Table 2). IV antibiotics were changed to vancomycin and piperacillin-tazobactam. He then underwent an interventional radiology-guided biopsy of the right ilium and aspiration of 20 mL purulent fluid from the right gluteal mass as recommended by the orthopedic oncology team. He remained intermittently febrile over the next two days, which gradually subsided with his right hip pain improvement. The bone biopsy revealed extensive acute and chronic inflammation with focal granulomatous change and no malignancy. The aspirated purulent fluid showed extensive necroinflammation, bacterial colonies most consistent with Actinomyces (Fig. 3) and no malignant cells. Right pelvic fluid histopath revealed the Splendore-Hoeppli phenomenon (sulfur granules and associated inflammation) (Fig. 4). The infectious disease (ID) team recommended continuing the piperacillin-tazobactam and stopping the vancomycin. Inflammatory markers were still elevated, whereas Quantiferon Gold Tuberculosis testing and serology for human immunodeficiency virus were negative (Table 2). A repeat contrasted CT scan of the chest, abdomen, and pelvis confirmed the prior pulmonary findings, whereas, in the pelvis, there was an interval increase in the size of the complex cystic mass indicative of abscess formation. He then underwent irrigation and debridement of the right hemipelvis and an open right ilium biopsy. Right ilium biopsy returned positive for acute and chronic osteomyelitis and negative for cancer. The right pelvic mass biopsy revealed fibrovascular tissue with acute and chronic inflammation, necrosis, hemorrhage, fibrosis, and negative for malignancy. Intraoperative tissue bacterial, mycobacterial and fungal cultures were negative. The pulmonary team performed the bronchoscopy and obtained an RUL protective specimen brush culture sample, bronchioalveolar lavage (BAL) for analysis, culture, and endemic fungal workup. Endobronchial ultrasound (EBUS) guided fine-needle aspiration on enlarged lymph nodes (stations 11 L,7, and 4 R) returned negative for infection and malignancy. BAL fluid analysis did not suggest any infection; however, the cultures returned positive for A. odontolyticus (Table 2). A. odontolyticus was sensitive to penicillin and resistant to clindamycin. Piperacillin-tazobactam was changed to ceftriaxone 2 g (gm) daily.
An oral dental surgeon evaluated his bad oral hygiene (Fig. 4). A transthoracic echocardiogram displayed an ejection fraction of 60% with normal cardiac valves and normal left and right ventricular systolic function. An X-ray Panorex revealed several missing teeth, multilevel caries, significant maxillary and mandibular lamina propria resorption, periapical lucency involving the remaining right maxillary molar, and possible retention cyst/opacification of the left maxillary sinus. He was recommended outpatient follow-up in three weeks to fix his bad teeth. A repeat MRI pelvis with contrast revealed a marked interval decrease in size of the complex multiloculated abscess involving the right retroperitoneum, gluteal muscles, and right paraspinal muscles, abnormal marrow signal, and osseous erosion of the right ilium. He was discharged home on IV ceftriaxone 2 gm daily to complete six weeks of antimicrobial therapy. Four weeks later, he followed up at the ID clinic with a decline in inflammatory markers (Table 2), and he was transitioned to oral amoxicillin 875 mg thrice a day for the next 12 months. Repeat CT chest with contrast at eight weeks post-discharge revealed resolving right upper lobe consolidation with residual linear opacities. A repeat MRI pelvis with and without contrast 12 weeks after discharge revealed markedly improved osteitis of the right innominate bone, surrounding soft tissue infection, and minimal persistent marrow changes within the right iliac bone. At the ninth-month ID clinic follow-up, he had his teeth fixed, recovered weight loss, and resumed daily activities. He completed 12 months of oral amoxicillin with complete recovery. (Fig. 5).