Cutaneous metastasis of a radiation-associated thyroid medullary carcinoma

Radiation port cutaneous metastases: reports of two patients whose recurrent visceral cancers presented as skin lesions at the site of previous radiation and literature review

Radiation therapy is associated with a variety of complications, including the development of primary skin cancers in the radiated region. However, it is rare for patients with visceral cancers who are treated with radiation therapy to subsequently develop cutaneous metastasis within the radiation port. We describe two patients with internal malignancies who developed cutaneous metastases within their radiation ports following radiotherapy. In addition, we used PubMed to perform an extensive literature review and identify additional reports of cutaneous metastasis within a radiation port. We excluded patients who developed melanoma or primary skin cancers in the radiation port. We also excluded patients with non-solid organ malignancies. Herein, we summarize the characteristics of 23 additional patients who experienced radiation port cutaneous metastases and explore possible mechanisms for the occurrence of radiation port cutaneous metastases.

Cutaneous metastases of internal tumors

Cutaneous metastases are relatively rare in clinical practice and their diagnosis requires a high index of suspicion because clinical findings can be subtle. These metastases reveal the presence of disseminated malignant disease and can lead to the diagnosis of unsuspected internal tumors or the spread or recurrence of an already diagnosed tumor. Early recognition of cutaneous metastases can facilitate prompt and accurate diagnosis resulting in early treatment; however, they are generally indicative of a poor prognosis. Some tumors have a predilection to metastasize to specific areas. Recognition of these patterns provides essential information that can guide the search for the underlying tumor.

Cutaneous metastasis of medullary thyroid carcinoma as the initial manifestation of an otherwise limited malignancy: a case report

Cutaneous metastasis from a thyroid carcinoma, particularly medullary thyroid carcinoma (MTC), are rare. Herein, we report the first case of MTC in which metastatic lesions, were also the earliest sign of the disease, affecting the skin. This is as well the third reported case of undetected MTC initially manifested by metastatic skin lesions. A 79-year-old white woman presented with painful skin lesions. The lesions were biopsied. Based on routine light microscopic examination and immunohistochemical study, MTC was the most likely diagnosis. Subsequent investigations identified the primary thyroid tumor, which also proved to be MTC. No other metastatic lesion could be demonstrated by further evaluations. This report illustrates a novel presentation of MTC. MTC metastases should be considered in the differential diagnosis of cutaneous lesions. It is important to histopathologically examine the lesions and perform appropriate immunohistochemical study that must include calcitonin and other neuroendocrine markers.

Skin metastasis: a pathologist's perspective

Skin metastasis is defined as the spread of malignant cells from a primary malignancy to the skin. It is one manifestation of systemic spread of cancer. The tumor cells originate either from an internal malignancy or from a primary skin cancer. This study presents a literature review concerning these issues as well as this author's experience encountered throughout 19 years of surgical pathology and dermatopathology practice. Several conclusions are evident. Generally, skin metastases are encountered in 0.7-9% of all patients with cancer and as such the skin is an uncommon site of metastatic disease when compared to other organs. There is usually a long-time lag between the diagnosis of the primary malignancy and the recognition of the skin metastases. However, these metastases may be the first indication of the clinically silent visceral malignancies. The regional distribution of the skin metastasis, although not always predictable, is related to the location of the primary malignancy and the mechanism of metastatic spread. The relative frequency of skin metastasis correlates with the type of primary cancer, which occurs in each sex. For instance, lung and breast carcinomas are the most common primaries that send skin metastasis in men and women, respectively. The head and neck region and the anterior chest are the areas of greatest predilection in men. The anterior chest wall and the abdomen are the most commonly involved sites in women. Skin metastases usually appear as non-specific groups of discrete firm painless nodules that emerge rapidly without any explanation. They vary in size from so tiny as to be of 'miliary lesions' to as large as 'Hen's egg size'. Some skin metastasis may mimic specific dermatological conditions such as cutaneous cyst, dermatofibroma, pyogenic granuloma, hemangioma, papular eruptions, herpes zoster eruptions, rapidly infiltrating plaques, alopecic patches, cellulitis and erysipelas. Histologically, the skin metastases usually show features reminiscent of the primary malignancy, but with variable degrees of differentiation. Molecularly, skin metastasis is an organized, non-random and organ-selective process orchestrated by interaction among several heterogeneous molecules, which are largely unknown. Metastasis to the skin is often a pre-terminal event that heralds poor outcome.

Four patients with cutaneous metastases from medullary thyroid cancer

Cutaneous metastasis from thyroid cancer, especially medullary thyroid cancer (MTC) is rare. We report four patients with cutaneous metastases from sporadic MTC, three women and one man, aged 50 to 69 years. They presented different cutaneous lesions phenotypes. The first patient had a remote history of MTC and initial presentation of the recurrence was a rapidly progressing cutaneous lesion; on subsequent disease staging, widely metastatic disease was discovered. The other three patients developed cutaneous metastases in the presence of known distant metastases, indicating systemic spread of thyroid cancer. Definitive diagnosis of cutaneous metastases of MTC was made on biopsy of the lesions with cells that stained positive for neuroendocrine markers. Accurate diagnosis of cutaneous metastasis from MTC is important because it is a negative prognostic factor indicative of multisystemic disease. Thus, MTC metastases should be included in the differential diagnosis of erythematous maculopapular eruptions and nodular lesions of the skin, especially when these metastases occur in the upper part of the body and if the patient has a history of MTC. The appearing of cutaneous metastasis is a negative prognostic factor since all the patients here described died within one year from the diagnosis of cutaneous metastases.

Thyroid carcinoma metastatic to the skin: a cutaneous manifestation of a widely disseminated malignancy

BACKGROUND

Cutaneous metastases develop in 2% to 9% of patients with an internal malignancy. Thyroid carcinoma metastatic to the skin is a rare clinical entity.

OBJECTIVE

Our purpose was to study the clinical and pathologic features and outcome in patients with cutaneous metastasis from thyroid carcinoma.

METHODS

The study included a retrospective analysis of six patients with skin metastases from thyroid carcinoma and a review of the English-language literature since 1964.

RESULTS

Including our six patients, 43 patients with skin metastases from thyroid carcinoma have been reported. Papillary carcinoma was the most common (41%), followed by follicular (28%), anaplastic (15%), and medullary carcinomas (15%). The scalp was the most common site of metastasis. For our patients, the average length of survival after diagnosis of cutaneous metastasis was 19 months.

CONCLUSION

Cutaneous metastasis from thyroid carcinoma is rare and occurs in the setting of disseminated neoplastic disease.

Radiation and thyroid disease

External irradiation of the thyroid causes the subsequent development of thyroid malignancies at an approximate rate of 5 per rad per million people per year. There is no certain lower threshold, but possibly doses above 3000 rads are less effective. The tumours produced are primarily differentiated malignancies typical of non-irradiated patients, and the clinical course is similar. Most radiation-associated malignancies followed treatment given for enlarged thymic glands, enlargement of the tonsils or adenoids, and acne. Currently patients are seen with radiation-associated thyroid disease following treatment of malignant tumours in the neck. Diagnostic manoeuvres are similar to those used in non-irradiated individuals, but multinodularity is probably an indication for operation. Because of the high incidence of multicentricity, we prefer near-total thyroidectomy if cancer is found. Prophylactic thyroid hormone administration is of uncertain value in preventing the development of tumours. X-ray to the thyroid also can induce other histologic abnormalities, including a high incidence of adenomas and hypothyroidism, and is associated with an increased incidence of autoimmune thyroid disease and possibly the development of exophthalmos and Graves' disease. In contrast to the obvious effects of external irradiation, 131I diagnostic tests and treatments have not been associated with a clearly increased incidence of thyroid malignancy.