*From the Division of Cardiothoracic Surgery, Guthrie Clinic and Robert Packer Hospital, Sayre, PA.
Correspondence to: Nche Zama, MD, PhD, Section of Cardiothoracic Surgery, One Guthrie Square, Guthrie Clinic, Sayre, PA 18840; e-mail: email@example.com
a patient who presented with a left lower lobe lung lesion suspicious
for cancer with possible hilar involvement. Intraoperatively, we found
a primary left phrenic nerve tumor, diaphragmatic eventration, and left
lower lobe atelectasis. He was successfully treated with total excision
of the tumor and plication of the diaphragm. Histopathology was
consistent with schwannoma of the phrenic nerve. Diaphragmatic
eventration is an uncommon presentation of a phrenic nerve schwannoma,
which is itself a rarely occurring tumor. Surgical resection of the
tumor and diaphragmatic plication is the primary modality of management
in these patients.
Neurogenic tumors represent one of the common causes of
mediastinal masses. In adults, the majority of these are benign and
found incidentally. They can originate in any neurogenic structure in
the mediastinum, including the sympathetic or parasympathetic chain,
intercostal nerves, and spinal ganglia. Schwannoma of the intrathoracic
phrenic nerve is a rare presentation and can pose difficult diagnostic
problems. Diaphragmatic eventration secondary to phrenic nerve tumors
is a very unusual occurrence. We describe a case of schwannoma of the
left phrenic nerve presenting with diaphragmatic paralysis and the
accepted surgical management.
This 68-year-old patient with a history of long-term smoking was
evaluated for recurrent chest discomfort and exertional dyspnea
occurring over a 12-month period. Chest radiography suggested a left
lower lobe mass with atelectasis. CT scan reading described an
irregular mass in the left lower lobe with distal atelectasis and
infiltrate extending posteriorly in the paravertebral gutter, with an
additional mediastinal soft-tissue mass in front of the left hilum
measuring 3 to 4 cm (Fig 1
). Results of bronchoscopy and transbronchial washings and biopsies were
On exploratory left thoracotomy, there was a firm, well-circumscribed,
completely encapsulated mass involving the left phrenic nerve at the
level of the hilum (Fig 2
). There was extensive atelectasis involving the lingula and left lower
lobe. There were no other lung parenchymal lesions or mediastinal
adenopathy. The pericardium did not appear to be involved. The left
hemidiaphragmatic leaf was severely attenuated and significantly
elevated. The hilar mass was resected along with the phrenic nerve from
the aortopulmonary window to the diaphragm. Plication of the left
hemidiaphragm was performed using 3–0 prolene running horizontal
mattress sutures. A wedge biopsy of the lingula was performed.
The phrenic nerve mass weighed 15 g and measured
4.6 × 2.8 × 2.3 cm. Histopathology showed a benign schwannoma
with a highly ordered cellular component (Antoni A) and a loose myxoid
component (Antoni B; Fig 3
). There were no significant pathologic findings in the lingular biopsy.
There were no postoperative complications. The patient was discharged
on the fourth postoperative day and is doing well at 1-year follow-up.
Neurogenic tumors represent 20% of all adult and 35% of all
pediatric mediastinal neoplasms.1 The majority of these
lesions in adults are benign, asymptomatic, and incidentally
found.1Schwannomas are benign, slow-growing neurogenic
tumors that arise from the sheath of a spinal nerve root or any
thoracic nerve and can extrinsically compress the associated nerve.
Malignant transformation is very uncommon. Schwannomas of the phrenic
nerve are very rare. In a review of 138 mediastinal tumors, only 1
originated from phrenic nerve.2Recognition of the normal
course of the phrenic nerve on computerized axial tomography may
decrease the potential pitfall of identifying the nerve as a metastatic
nodule.3Management of these tumors is primarily surgical
excision, which is curative with recurrences being rare.4
Acquired diaphragmatic eventration is an uncommon condition in adults
that results in marked weakness and elevation of the diaphragm. The
most common causes are birth trauma, injury during cervical and
thoracic operations, invasion by tumors, and pleural or pulmonary
infections.5Mediastinal neurofibroma can cause unilateral
diaphragmatic paralysis in von Recklinghausen disease.6In
a review of 142 patients with unexplained diaphragmatic eventration,
phrenic nerve involvement with tumor was diagnosed in only 5
patients.7 Of these, four patients had bronchogenic
carcinoma with malignant phrenic nerve involvement and the fifth
patient had metastatic hepatocellular carcinoma. All five patients
eventually died of their neoplasm. Surgery is indicated in symptomatic
eventration or in cases of very large eventrations, even if
asymptomatic. Plication of the diaphragm is the procedure of
choice.5 Reinforcement with a synthetic mesh may be
In conclusion, we report a unique case of a rarely occurring schwannoma
of the left phrenic nerve presenting as a soft-tissue mass in front of
the left hilum and associated with an elevated, paralyzed left
diaphragmatic leaf. The diaphragmatic eventration was the cause of the
atelectasis of the left lower lobe that was interpreted as cancer, and
the phrenic nerve tumor itself appeared as hilar lymphadenopathy. The
preoperative evaluation was suggestive of bronchogenic carcinoma with
hilar lymphadenopathy and phrenic nerve invasion. Excision of the tumor
and plication of the diaphragm were useful in alleviating the
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