Cutaneous metastasis from anaplastic thyroid carcinoma exhibiting exclusively a spindle cell morphology. A case report and review of literature.
Anaplastic thyroid carcinoma is a highly aggressive cancer accounting for 1-2% of thyroid malignancies. Cutaneous metastases from anaplastic thyroid carcinoma are exceedingly rare. We report a 65-year-old woman with anaplastic thyroid carcinoma (BRAF V600E mutation) who had lymph node metastases (pT4 N1b) treated by total thyroidectomy, postoperative radiotherapy, adjuvant chemotherapy (paclitaxel and pazopanib) and targeted therapy (vemurafenib). Nine months after initial diagnosis, radiographic studies revealed multiple pulmonary metastases. A dermatologic examination showed a solitary 1.2-cm chest nodule. Skin biopsy from this nodule revealed infiltrative dermal spindle cells arranged in poorly formed fascicles. Immunohistochemical studies demonstrated the tumor cells to be PAX-8 (+), pancytokeratin (+, focally), TTF-1 (-) and SOX-10 (-). Comparison with the patient's primary anaplastic thyroid carcinoma revealed focal areas of poorly differentiated spindle cells morphologically similar to the malignant spindle cells in the skin biopsy. Together, these findings confirmed the diagnosis of anaplastic thyroid carcinoma metastatic to skin. Cutaneous metastasis of anaplastic thyroid carcinoma composed exclusively of spindle cells broadens the histologic differential diagnosis of cutaneous spindle cell malignancies and presents further diagnostic challenges. PAX-8 may be useful in discerning the spindle cell component of anaplastic thyroid carcinoma from other spindle cell malignancies in the skin.
Department of Pathology, Section of Dermatopathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Richard
R
Danialan
Department of Pathology, Section of Dermatopathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Michael T
MT
Tetzlaff
Department of Pathology, Section of Dermatopathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.|Department of Dermatology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Carlos A
CA
Torres-Cabala
Department of Dermatology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Stephen R
SR
Mays
Department of Pathology, Section of Dermatopathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.|Department of Dermatology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Victor G
VG
Prieto
Head and Neck Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Diana
D
Bell
Department of Pathology, Section of Dermatopathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.|Department of Dermatology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Jonathan L
JL
Curry
D000368:Aged; D005260:Female; D006801:Humans; D020125:Mutation, Missense; D009362:Neoplasm Metastasis; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D012509:Sarcoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D065646:Thyroid Carcinoma, Anaplastic / Q000235:genetics / Q000378:metabolism / Q000473:pathology
D009363:Neoplasm Proteins
anaplastic thyroid carcinoma; cutaneous metastases; spindle cells