Management Considerations for Differentiated Thyroid Carcinoma Presenting as a Metastasis to the Skull Base

Unmasking the Silent Invader: A Rare Case of Follicular Thyroid Carcinoma With Skull Metastasis and an Uncommon KRAS Q61R Mutation

Follicular thyroid carcinoma (FTC) is a noteworthy subtype of thyroid cancer known for its tendency to metastasize through the bloodstream, usually to the lungs and bones. This case report examines an exceptionally rare instance involving an 81-year-old female presenting with an unusual metastatic scalp lesion. Remarkably, this aggressive metastasis originated from a thyroid lesion as small as 0.7 cm. Lab findings, including suppressed TSH and elevated T3 levels, revealed subclinical hyperthyroidism, adding another layer of rarity to this FTC case. Molecular profiling identified a rare KRAS Q61R mutation, providing potential insight into the case's aggressive behavior and underscoring the importance of genetic assessment in FTC. This report emphasizes the critical role of comprehensive diagnostic evaluations, including histopathological assessments, in properly diagnosing and managing FTC, especially when clinical presentations defy conventional paradigms.

A double mutation of BRAF L597Q and V600E in situ and solitary brain metastasis of occult papillary thyroid carcinoma: A case report

RATIONALE

The rare BRAF L597Q (c.T1790A) point mutation has been previously reported in childhood acute lymphoblastic leukemia. We present the first rare case of occult papillary thyroid carcinoma with BRAF L597Q mutation in a Tibetan patient.

PATIENT CONCERNS

A 57-year-old male patient presented with a protruding mass on the left forehead for 2 years and numbness in the right limb for 3 weeks.

DIAGNOSES

The patient had a double mutation of BRAF L597Q and V600E in 2 separate lesions at thyroid and brain, the immunohistochemical staining showed that the cytokeratin (CK), thyroglobulin (Tg) and thyroid transforming factor-1 (TTF-1) were immunoreactive. All the findings supported the diagnosis of solitary brain metastasis of occult papillary thyroid carcinoma.

INTERVENTIONS

The patient underwent left frontal lobe metastasis (thyroid cancer) resection that involved craniectomy and artificial skull repair.

OUTCOMES

During the 24-month follow-up, no postoperative complications or recurrence and metastasis were found.

LESSONS

This is the first case of solitary brain metastasis of occult papillary thyroid carcinoma with double mutation of BRAF L597Q and V600E in 2 separate lesions reported in the literature. Our study extends the disease spectrum of occult papillary thyroid carcinoma and suggests that the BRAF L597Q mutation might play a specific role in inducing the solitary brain metastasis of occult papillary thyroid carcinoma in a Chinese Tibetan patient, but the detailed molecular mechanism remains to be confirmed by a large number of functional experiments and clinical research.

Concurrent metastases of papillary thyroid carcinoma to the scalp and Meckel's cave

We present the case of a 65-year-old man with severe headaches and unilateral facial weakness, seen in consultation by the dermatology service to rule out primary cutaneous melanoma after brain imaging identified an enlarging mass within the right trigeminal (Meckel's) cave. Examination revealed only a pair of erythematous papules on the scalp, for which biopsy demonstrated metastatic papillary thyroid carcinoma. Further evaluation and subsequent thyroidectomy confirmed the origin of widespread internal disease, followed by definitive excision of scalp lesions and multimodal management of systemic involvement. Whereas presentation of metastasis to the skin is highly variable, a low threshold for biopsy may allow for histological identification of internal disease not otherwise considered in the clinical differential.

Plexus and peripheral nerve metastasis

Cancer in the form of solid tumors, leukemia, and lymphoma can infiltrate and metastasize to the peripheral nervous system, including the cranial nerves, nerve roots, cervical, brachial and lumbosacral plexuses, and, rarely, the peripheral nerves. This review discusses the presentation, diagnostic evaluation, and treatment options for metastatic lesions to these components of the peripheral nervous system and is organized based on the anatomic distribution. As skull base metastases (also discussed in Chapter 14) result in cranial neuropathies, these will be covered in detail, as well as cancers that directly infiltrate the cranial nerves. Particular emphasis is placed on the clinical, imaging, and electrodiagnostic features that differentiate neoplastic plexopathies from radiation-induced plexopathies. Neurolymphomatosis, in which malignant lymphocytes invade the cranial nerves, nerve roots, brachial and lumbosacral plexuses, and peripheral nerves, is a rare manifestation of lymphoma and leukemia. Diagnoses of neurolymphomatosis are often missed or delayed given its varied presentations, resulting in poorer outcomes. Thus this disease will also be discussed in depth.

Skull base metastasis from papillary thyroid carcinoma: a report of three cases

Skull base metastasis from differentiated thyroid carcinoma, including papillary and follicular thyroid carcinoma, is a rare manifestation. Herein, we present three cases of skull base metastasis of papillary thyroid carcinoma. The mean age of the patients was 68.6 (65–74) years, and the mean interval between initial diagnosis and skull base metastasis was 56.3 (28–89) months. Cranial nerve palsies were seen in all patients. Intensity modulated radiation therapy to deliver 6,000–6,600 cGy to the skull base metastasis was given to all patients, in addition to partial resection in one patient. At the time of last follow-up, all skull base metastases were well controlled.

Skull metastasis revealing a papillary thyroid carcinoma

Although thyroid carcinoma is a relatively common form of malignancy, metastatic spread to the skull is rare. Here, we report a case of papillary thyroid carcinoma with frontal and parietal metastasis. A 61-year-old Chinese woman presented with a one year history of a growing mass on the center of the frontal and parietal bone, initially thought to be meningioma. Biopsy of the skull base mass after intracalvarium excision, indicated a tumor of thyroid origin. One month later the patient underwent a total thyroidectomy. Pathological examination confirmed a diagnosis of papillary thyroid carcinoma with frontal and parietal bone metastasis. Based on this experience, the key to successful management of the skull metastasis of thyroid carcinoma is prompt diagnosis and appropriate treatment. Skull metastasis should be considered at the outset of the clinical course of papillary thyroid cancer. To facilitate this, patients should be meticulously investigated by a multidisciplinary team to improve quality of life.

Yamada S, Miyamoto S, Yamada S, Son JH, Nishido H, Ide F, Nagashima H, Sugaya M, Hirohata T, Mizutani A, Okinaga H, Ishii Y, Tahara S, Teramoto A, Osamura RY, Yamazaki K, Ishida Y. Clinicopathological and molecular histochemical review of skull base metastasis from differentiated thyroid carcinoma

Skull base metastasis from differentiated thyroid carcinoma including follicular thyroid carcinoma (FTC) and papillary thyroid carcinoma (PTC) is a rare clinical entity. Eighteen FTC cases and 10 PTC cases showing skull base metastasis have been reported. The most common symptom of skull base metastasis from FTC and PTC is cranial nerve dysfunction. Bone destruction and local invasion to the surrounding soft tissues are common on radiological imaging. Skull base metastases can be the initial clinical presentation of FTC and PTC in the presence of silent primary sites. The possibility of skull base metastasis from FTC and PTC should be considered in patients with the clinical symptoms of cranial nerve dysfunction and radiological findings of bone destruction. A variety of genetic alterations in thyroid tumors have been identified to have a fundamental role in their tumorigenesis. Molecular histochemical studies are useful for elucidating the histopathological features of thyroid carcinoma. Recent molecular findings may provide novel molecular-based treatment strategies for thyroid carcinoma.

Surgical management of cranial base metastases

BACKGROUND

Cranial base metastases (CBM) are rare and have received limited attention in the medical literature. Questions remain regarding the role of surgery, if any, in the management of these tumors.

OBJECTIVE

To report surgical outcomes in a consecutive series of patients with CBM and to better define the role of surgery in their management.

METHODS

Twenty-seven patients with CBM underwent surgery between 1996 and 2009 at MD Anderson Cancer Center. A retrospective review of their prospectively collected data was performed after obtaining institutional review board approval. The median patient age was 52 years. The most common pathology was renal cell carcinoma (6 patients). Surgical indications were worsening neurological deficit, disfiguring mass, and the need for a diagnosis.

RESULTS

Gross total resection was achieved in 59% of the cases. The median survival was 11.4 months. The median progression-free survival was 5.8 months. A Karnofsky Performance Scale score less than 90, dural invasion, and brain invasion were associated with a shorter survival. Seven patients were neurologically intact preoperatively; all of them remained intact after surgery. Among all patients with preoperative neurological deficit, 11 remained stable, 7 improved, and 2 had worsening of their deficit postoperatively.

CONCLUSION

The goal of surgery for CBM is to provide symptom relief and to preserve functional status in well-selected cases. Patient selection is critical because the surgery is usually palliative, and only a minority of patients are surgical candidates. Radiation therapy remains the management option of choice for the majority of patients.

Skull base metastasis from follicular thyroid carcinoma -two case reports-

A 58-year-old woman and a 71-year-old woman presented with extremely rare skull base metastases from follicular thyroid carcinoma (FTC). Surgical removal and external radiotherapy were performed followed by iodine-131 ((131)I) brachytherapy and thyroid hormone administration. The metastatic tumors in the skull base were well controlled. Treatment for skull base metastasis from FTC includes surgical debulking of the metastatic lesion, as well as complete resection of the thyroid gland, followed by internal irradiation with (131)I, external irradiation, and administration of thyroid hormone to prevent tumor growth by suppression of endogenous thyroid-stimulating hormone. Skull base metastases may be the initial clinical presentation of FTC, with silent primary sites. The possibility of skull base metastasis from FTC should be considered in patients with clinical symptoms of cranial nerve dysfunction and radiological findings of bone destruction.