|Year : 2014 | Volume
| Issue : 1 | Page : 44-46
Isolated neurofibroma of the Thyroid Gland
Prakash K Sasmal1, Kanakalata Dash2, Raghumani Mohanty3, Kumudini Devi2
1 Department of Surgery, Institute of Medical Sciences and SUM Hospital, Bhubaneshwar, Odisha, India
2 Professor in Pathology, Institute of Medical Sciences and SUM Hospital, Bhubaneshwar, Odisha, India
3 Professor and Head of Department in Pathology, Institute of Medical Sciences and SUM Hospital, Bhubaneshwar, Odisha, India
|Date of Web Publication||14-Jul-2014|
Prakash K Sasmal
Department of Surgery, The Institute of Medical Sciences and SUM Hospital, Bhubaneswar - 751 030, Odisha
Source of Support: None, Conflict of Interest: None
Neurofibroma is a common benign tumor usually arising from a cutaneous or peripheral nerve. Neurofibromatosis involving only the thyroid gland is a rare phenomenon and so far only two cases have been reported in the literature. We describe neurofibromatosis in a 46-year old male presenting with a gradually increasing isolated swelling over left anterior triangle of neck for two years. No toxic or pressure symptoms were reported. Fine needle aspiration cytology (FNAC) of the swelling was suggestive of colloid goiter with spindle-cell component. The patient underwent a left hemithyroidectomy. Histology and immunehistochemistry data confirmed it to be neurofibroma of the thyroid gland. Since the last two years, the patient is doing well. Isolated neurofibroma of the thyroid gland is very rare. Surgical excision is the treatment of choice depending on the extent of involvement of the gland. The entity although rare has to be considered in the differential diagnosis of a thyroid swelling.
Keywords: Neurofibroma, neurofibromatosis, schwannoma, thyroid, thyroidectomy
|How to cite this article:|
Sasmal PK, Dash K, Mohanty R, Devi K. Isolated neurofibroma of the Thyroid Gland. Arch Int Surg 2014;4:44-6
| Introduction|| |
Neurofibroma is a benign tumor arising in anatomically discernible cutaneous and peripheral nerves. This tumor occurs sporadically or is associated with generalized neurofibromatosis (NF-1). Primary peripheral nerve sheath tumors (PNSTs) of the thyroid gland are exceptionally rare tumors that usually present as asymptomatic neck nodules in adults.  Neurofibromas of the thyroid gland are usually associated with generalized NF-1. Whereas isolated neurofibromas of the thyroid gland are extremely rare. Only two cases of primary neurofibroma of the thyroid gland , and one case from thyroid capsule  have been reported till date. We report another case of intrathyroidal neurofibroma presenting with anterior neck swelling.
| Case Report|| |
A 46-year-old male presented with a painless progressive anterior neck swelling for the last two years. There were no symptoms of hypothyroidism or hyperthyroidism or causing pressure effects. There were no other swellings in any part of the body. Physical examination revealed a non-tender, firm to hard enlargement of left-lobe of the thyroid gland with minimal deviation of the trachea. The swelling was clinically suspected to be simple, diffuse goiter of left-lobe of thyroid gland.
FNAC of the swelling revealed benign thyroid follicular cells along with benign appearing spindle cells in fascicles and singles interspersed in a colloid background. The diagnosis was colloid goiter with accompanied spindle cell component. Ultrasonography of the neck revealed a solid mixed heteroechoic enlargement of left lobe of the thyroid gland with no cystic changes or cervical adenopathy.
The patient underwent a left hemithyroidectomy, as only the left-lobe of the thyroid gland was enlarged. Post-operative cut-section of the specimen revealed replacement of the entire left-lobe by a grayish white lobulated mass measuring about 10 × 8 cm. Gross pathological examination revealed capsulated mass with lobular surface measuring (10 × 8 × 6) cm. The cut surface showed a well-circumscribed non-encapsulated solid gray white mass with intervening mucoid areas and thin rim of peripheral compressed thyroid tissues [Figure 1]. Microscopically the un-encapsulated neoplastic tissue consisted of spindle shaped cells with wavy and tapered nuclei arranged in fascicles intermingled with collagen bundles. Mucoid changes at some places were also noted. The normal thyroid tissue was compressed towards the periphery [Figure 2]. In addition, few thyroid follicles lined by benign follicular epithelial cells and filled with colloid were seen interspersed within the tumor. No "Antoni A" pattern with verocay bodies or perivascular hyalinization were noted. Based on the morphological features, a primary neurofibroma of the thyroid gland was diagnosed. Immunohistochemical (IHC) examination for S-100 protein showed focal intense positivity [Figure 3] and the diagnosis was confirmed as neurofibroma.
|Figure 2: H&E (× 100) stain showing unencapsulated tumor tissue with peripheral compressed normal thyroid tissue towards left side|
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|Figure 3: IHC for S-100 protein highlights focal intense positivity (× 400)|
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The postoperative period was uneventful. Follow up for two years after surgery revealed that the patient is doing well without any recurrence.
| Discussion|| |
Neurofibroma is a benign tumor arising from a cutaneous or peripheral nerve. This tumor occurs sporadically or is associated with NF-1. Neurofibromas mainly occur on the trunk and extremities but may also be found in the head and neck regions. This tumor rarely arises from the thyroid gland, but when that occurs, the tumor is commonly associated with NF-1 or von-Recklinghausen disease.  The thyroid gland receives fibers from sympathetic and parasympathetic divisions of the autonomic nerve system. PNSTs of the thyroid gland are exceptionally rare and usually present as asymptomatic neck nodules in adults.  PNSTs of the thyroid can be classified into benign and malignant. Benign peripheral nerve sheath tumors include neurofibromas and schwannomas. Only two cases of isolated neurofibroma of the thyroid have been reported. , Schwannomas are typically benign, slow-growing tumors that originate from neuronal schwann cells, with a clinical picture depending on the anatomic size and site. Only 17 cases of schwannomas of the thyroid gland are reported in literature.  Malignant PNSTs have been very rare and three cases have been reported.
Neurofibroma of the thyroid gland may assume any of the three growth patterns: Localized, diffuse or plexiform. The localized form is seen most commonly as a superficial, solitary tumour in normal individuals. Diffuse and plexiform neurofibromata have a close association with NF-1. Histologically, neurofibroma of thyroid has to be differentiated from schwannoma. The absence of encapsulation and two types of Antoni areas plus lack of uniformly intense immune staining for S-100 protein distinguish neurofibroma from schwannoma.
Neurofibroma of thyroid gland presenting as hard, fibrous mass is usually confused with Riedel's thyroiditis. The latter is a diffuse process thought to be the end-stage of thyroiditis. Reidel's thyroiditis on histology can be distinguished by atrophic thyroid acini trapped in the hyalinizing fibrous tissue, which may contain inflammatory infiltrate, chiefly lymphocytes and plasma cells.
In our case, there was no other diffuse thickening or swelling in the skin and subcutaneous tissue. There were no features of NF-1 like lightly pigmented café-au-lait spots in the skin and Lisch nodules in the iris. It is seldom diagnosed preoperatively by FNAC. The entity is only confirmed by histopathology and IHC for S-100.
The treatment of neurofibroma of the thyroid gland is not clearly defined in the literature. As this is a benign condition, hemithyroidectomy of the affected side is rational. In our case, the patient is on follow-up for the last two years and is doing well. But had there been bilateral nodules in the thyroid gland either clinically or radiologically or cervical adenopathy, then total thyroidectomy would have been justified.
| Conclusion|| |
Isolated neurofibroma of the thyroid gland is very rare. However, the association with NF-1 and medullary carcinoma of the thyroid exists in literature and needs to be excluded. Although the condition is rare still is not uncommon. Surgical excision is the treatment of choice with total thyroidectomy done only when indicated.
| References|| |
|1.||Kandil E, Abdel Khalek M, Abdullah O, Dali D, Faruqui S, Khan A, et al. Primary peripheral nerve sheath tumors of the thyroid gland. Thyroid 2010;20:583-6. |
|2.||Capelli A, Guernelli L, Bertoni F, Fuga G. Neurofibroma of thyroid (report of a case). Arch Chir Torac Cardiovasc 1975;32:23-7. |
|3.||Gaud U, Shukla M, Kumar M, Pandey M. Isolated intrathyroidal neurofibroma. Otolaryngol Head Neck Surg 2009;141:300-1. |
|4.||Ciardi A, Pecorella I, Thrmbetta G, Memeo L, Quarto AD, Tondo UD. An unusual case of neurofibroma of the thyroid capsule. Pathol Oncol Res 1997;3:293-5. |
|5.||Severo MD, Rosa VD, DeCarli DM, Beck Mde O, Danbermam MF. Neurofibroma of thyroid in a patient with neurofibromatosis type 1. Arq Bras Endocrinol Metabol 2008;52:131-3. |
|6.||Goldstein J, Tovi F, Sidi J. Primary schwannoma of the thyroid gland. Int Surg 1982;67:433-4. |
[Figure 1], [Figure 2], [Figure 3]