SCHWANNOMAS OF ADRENAL GLAND AND POSTERIOR MEDIASTINUM

SCHWANNOMAS OF ADRENAL GLAND AND POSTERIOR

MEDIASTINUM

奇美醫學中心內分泌新陳代謝科楊純宜醫師

GENERAL DATA

• 林小姐 , • A 30-year-old Taiwanese woman• Unmarried• Occupation: insurance employee• Hobby: fitness• 1st time Hospitalization date: from 95-5-31 to 95-6-12• 2nd time Hospitalization date: from 95-6-19 to 95-7-17

Chief complaint

• left anterior chest discomfort (sternal area) and left flank pain for one week.

Present illness

1. Denied any systemic illness before.

2. Visit exercise center frequently

3. Felt anterior chest wall pain (over sternal area) and left flank pain in recent days

4. Visit CM OPD on 95-5-23, CXR revealed masses over mediastinum and superimposing left hilum.

5.Arranged admission on 95-5-31

Past and personal history

• Denied of any systemic illness before

• No major operation

• No smoking

• No alcoholic drinking

Hematology95-5-31 95-7-6

WBC 5700 13600

RBC 4.07 x 106 3.47 x 106

Hb 12.7 10.8

Hct 36.9% 31.7%

MCV 90.6 91.4

MCH 31.3 31.2

MCHC 34.6 34.1

PLT 234K 251K

Band 0 0

Segment 69.7 84.8

Lymphocyte 24.0 8.7

Monocyte 5.6 6.3

PT 11.4 (11.1)

APTT 27.8 (29.5)

Biochemistry data95-5-31 95-6-4 95-7-5 95-7-6

BUN 11 13

Cr 0.8 0.8 0.7

Glu 75 84

GOT 18

GPT 10 32

Na 141.6 140.8 139.1

K 4.24 3.87 4.58

Cl 101.8

Ca 9.2

P 4.7

Stool routine

• Occult: -

• Parasite Ova-Direct: -

• Microscopic WBC: -

• Microscopic-Ep. Cell: -

• Appearance: soft

• Color: Brown

Urine routine• Appearance: Clear• Color: Yellow• PH: 6.5• Protein: -• Glucose: -• Ketone body: -• Urobilinogen: 0.1• Bilirubin: -• Occult: -• Specific gravity: 1.025• WBC: (-)• RBC: (-)• Bacilli: (+)• Cast: (-)• Crystal: (-)

Chest X-ray

• showed left paraspinal lobulated soft tissue tumor.

Chest computed tomography (CT)

• revealed several well-marginated heterogeneously enhancing masses with central low density along left paraspinal region and a heterogenous enhancing mass over left adrenal region. R/O MEN type II, Pheochromocytoma with paragangliomas.

Endocrine consultation

• CM doctor consult endocrine doctor on 6/2

• Endocrine section take over the case on 6/3

• Arranged Endocrine study & MRI of adrenal gland

Endocrinological studies (1)

• Serum calcitonin: <14.0 pg/ml (<42)

• Cortisol (Random): 10.85 ug/dl

• ACTH: 29.4 pg/ml (9-52)

• Aldosterone: 117.2 pg/ml

• Renin: 1.95 ng/ml

Endocrinological studies (2)

24 hr urine: 2000cc • free cortisol: 5.1 ug/day (<60)• VMA: 3.7 mg/day (1.0-7.5)• 17-KS:9.12 mg/day (6-14)• 17-OHCS: 9.68 mg/day (2-8)• Adrenaline: 4.5 ug/day (<22.4)• Noradrenaline: 33.3 ug/day (11.1-85)• Dopamine: 264 ug/day (50-450)

Magnetic resonance imaging (MRI) of adrenal gland

• revealed a 6.3 cm left adrenal tumor, retrocrual and thoracic paraspinal tumors.

Consult CS & GU section

• CS doctor take over the case & arrnage OP

• Due to personal problem, patient discharge on 95-6-13

• Readmission on 95-6-18 & received CS OP on 95-6-19

Operation

• 95-6-19 Patient received tumor removal of posterior mediastinum

• Admitted at ICU from 96-6-19 to 96-6-29

• 95-7-3 GU take over the case

• 95-7-6 GU performed left laparoscopic adrenalectomy.

Pathological finding

• Pathological examination revealed ovoid to spindle schwann cells arranged in fascicles with stromal myxoid changes.

• Immunohistochemical examination revealed tumor cells positive for S-100 protein but not CD34, diagnostic for schwannoma.

Postoperative course

• The postoperative course was smooth. After one month hospitalization, the patient was discharged in good condition on 96-7-18.

Final diagnosis

• Schwannomas of adrenal gland and posterior mediastinum

Discussion

Adrenal incidentalomas

• A heterogenous group of pathological entities, including benign or malignant adrenocortical or medullary tumors, hormonally active or inactive lesions, which are identified incidentally during the examination of nonadrenal-related abdominal complaints

• Pheochromocytomas 1.5%-23%• Nonpheochromocytoma: ganglioneuroma, gnaglio

neuroblastoma, neuroblastoma, and malignant or benign schwannoma

Schwann cells

• The Schwann cells are the cells that make the myelin in the peripheral nervous system (PNS).

• In contrast to the oligodendrocytes of the central nervous system, each Schwann cell myelinates a single axon.

• Also, Schwann cells lay down a basement membrane around themselves, unlike oligodendrocytes.

• Schwann cells are very important in regeneration a damaged peripheral nerve.

• Schwann cells can also form tumors, called schwannomas.

Schwannoma

• Most schwannomas occur in the head, neck, stomach or limbs with a few cases occurring in the retroperitoneal space

• In benign schwannoma occurring in retroperitoneal space, tumors are most commonly located near the adrenal gland.

Pathophysiology• Schwannomas arise from the nerve sheath and consist

of Schwann cells in a collagenous matrix. • Histologically, the terms Antoni type A neurilemoma an

d type B neurilemoma are used to describe varying growth patterns in schwannomas. Type A tissue has elongated spindle cells arranged in irregular streams and is compact in nature. Type B tissue has a looser organization, often with cystic spaces intermixed within the tissue. The cystic spaces can result in high signal intensity on T2-weighted MRIs.

• Tumors originating in Schwann cells can be detected at immunohistochemical examination by virtue of their positive results with S-100 antigen tests, collagen IV, laminin and absence of reactivity for keratin, muscle related antigens, and CD34.

• It typically has dense areas called Antoni A (black arrow) and looser areas called Antoni B (blue arrows). The cells are elongated (spindle shaped) and the nuclei have a tendency to line up as you see here in the Antoni A area. Like normal Schwann cells, schwannoma cells are each surrounded by a basement membrane.

This is an example of a schwannoma

The resected tumor was firm and had a yellowish-white

cut surface

Schwannoma

• Schwannoma and neurofibroma are benign peripheral nerve neoplasms, represent the most common mediastinal neurogenic tumors, and rarely degenerate into malignant tumors of nerve sheath origin

Neurofibromatosis 2 (NF2) and Schwannoma

• Neurofibromatosis 2 (NF2) is an autosomal dominant disorder that causes nervous system tumors and ocular abnormalities such as early onset lenticular opacities. Vestibular schwannoma also noted.

• CN schwannomas are usually isolated lesions, except when they are associated with neurofibromatosis type 2 (NF2), a rare autosomal dominant disorder occurring in approximately 1 live birth in 50,000.

• NF2 is also called the multiple inherited schwannomas, meningiomas, and ependymomas (MISME) syndrome.

• NF2 is characterized by bilateral vestibular schwannomas. Schwannomas of the other CNs occur more frequently in NF2, and the presence of one of the rare CN schwannomas should suggest the possibility of NF2. Meningiomas and intramedullary ependymomas of the spinal cord also occur in NF2

CNS SCHWANNOMA• Schwannomas account for 6-8% of intracranial ne

oplasms. • Autopsy studies have shown that the incidence rat

es of occult vestibular schwannomas are as high as 2.7%.

• A study of patients undergoing MRI for indications other than the evaluation of schwannoma revealed an estimated prevalence of 0.07%.

• Vestibular schwannomas are the most common CN schwannomas, followed by trigeminal and facial schwannomas and then glossopharyngeal, vagus, and spinal accessory nerve schwannomas.

• Schwannomas involving the oculomotor, trochlear, abducens, and hypoglossal nerves are rare.

Other characters of schwannoma

• Mortality/Morbidity: Morbidity resulting from schwannomas includes nerve dysfunction and brainstem compression. Mortality can result from mass effect with brainstem compression.

• Race: No racial predilection has been described in schwannomas.

• Sex: No sex predilection has been described in schwannomas.

Detection of Schwannomas• 123I-metaiodobenzylguanidine (MIBG) scan-reliable

morphofunctional technique to evaluate catecholamine turnover in adrenal tumors

• Computed tomography (CT) scan: anatomy of tumor, cystic lesions

• Magnetic resonance imaging (MRI): MRI provides the highest degree of soft tissue resolution, it can provide images in multiple planes

Surgical intervention

• Transabdominal approach-suitable for pheochromocytoma and bilateral adrenal tumor, but postoperative recovery was slow

• Translumbar approach-40% pleural injury

• Laparoscopic adrenalectomy: is safe and feasible for diagnosis and treatment of benign adrenal or retroperitoneal schwannoma, recovery fast

Prognosis

• Retroperitoneal schwannoma is a primary neural benign tumor with a good prognosis

• The management is surgical

Conculsion

• Schwannoma of both adrenal gland and posterior mediastinum are extremely rare

• Although most schwannoma are benign

• Long term follow up is mandatory