真菌症に起因する上顎骨および頭蓋底骨壊死：悪性腫瘍の誤診の可能性

Mucormycosis originated total maxillary and cranial base osteonecrosis: a possible misdiagnosis to malignancy.

抄録

背景:

本症例は、当初悪性腫瘍が疑われた上顎骨骨壊死から頭蓋底に拡大した粘菌症由来の症例である。当初は溶骨性肉腫病変が疑われたが，生検により侵襲性粘菌症が証明され，上顎骨全壊および頭蓋底と診断された．

BACKGROUND: This is a case of mucormycosis originated osteonecrosis of the maxilla extended to the cranial base, initially suspected of malignancy. The patient was first suspected with osteolytic sarcomatous lesion but was later diagnosed with total maxillary necrosis and cranial base through biopsy-proven invasive mucormycosis.

症例提示:

71歳男性が原因不明の上顎骨全壊で受診した。CT、MRIの結果、頭蓋底の骨破壊を伴う広範な溶骨性変化が認められ、PET-CTでは悪性腫瘍を疑う部位に不規則な代謝亢進病変が認められた。初回の生検結果では組織の炎症が認められたのみであった。そこで，さらに数回の内視鏡的生検を咽頭後壁から施行した。患者は最終的に粘菌症とそれに伴う骨髄炎とそれに続く骨壊死と診断された。診断が確定したため，全身麻酔下で壊死した骨の上顎部分切除術が行われた．4 週間の経過観察では，粘膜の完全治癒を認め，上顎と頭蓋底の病変の再発・悪化は認められなかった．

CASE PRESENTATION: A 71-year-old male was presented with unknown total maxillary osteonecrosis. CT and MRI results showed extensive osteolytic change with bone destruction of the cranial base, and PET-CT showed irregular hypermetabolic lesion in the area suspected of malignancy. The first biopsy results only presented tissue inflammation. Thus, several further endoscopic biopsy were performed through posterior pharyngeal wall. The patient was eventually diagnosed with mucormycosis and associated osteomyelitis with subsequent bone necrosis. With confirmed diagnosis, partial maxillectomy of the necrosed bone was performed under general anesthesia. At the 4 week follow-up, the patient showed full mucosal healing and no recurrence or aggravation of the maxilla and cranial base lesion was observed.

結語:

頭蓋底骨髄炎は，非定型症状の正確な診断，タイムリーな診断，外科的介入，抗真菌剤，抗生物質の適切な併用療法が，適切な治療計画のために重要である．また、生検やCTスキャンは骨壊死と悪性腫瘍の鑑別に不可欠である。

CONCLUSIONS: Accurate diagnosis of atypical symptoms, timely diagnosis, and proper combination therapy of surgical intervention, antifungal agent, and antibiotic use for skull base osteomyelitis are all critical for proper treatment planning. In addition, biopsy and CT scans are essential in differentiating osteonecrosis from malignancy.