|Year : 2019 | Volume
| Issue : 2 | Page : 162-164
Thyroxine-Induced preradial myxedema
Mary Zothanpuii Chhangte, Shikha Verma, Binod Kumar Thakur, Anita Marak
Department of Skin and STD, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences, Mawdiangdiang, Shillong, Meghalaya, India
|Date of Web Publication||15-Mar-2019|
Department of Skin and STD, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences, Mawdiangdiang, Shillong - 793 018
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Localized myxedema is most commonly described in patients with hyperthyroidism, especially Graves' disease. Although pretibial myxedema generally appears as indurated plaques on the shins, it has also been rarely reported in other areas such as the face, shoulders, arms, and abdomen. We report a rare case of preradial myxedema in a hyperthyroid patient who was taking thyroxine post thyroidectomy for goiter. To the best of authors' knowledge, this is the first case of preradial myxedema, due to long-term intake of thyroxine, reported in the English dermatological literature.
Keywords: Hyperthyroidism, preradial myxedema, thyroxine
|How to cite this article:|
Chhangte MZ, Verma S, Thakur BK, Marak A. Thyroxine-Induced preradial myxedema. Indian Dermatol Online J 2019;10:162-4
| Introduction|| |
Pretibial myxedema (PTM) is characterized by bilateral thickening and induration of the skin on the shins and dorsa of the feet. The toes, thighs, upper extremities, and face can rarely be involved., We report a rare case of thyroxine-induced preradial myxedema in a 70-year-old patient.
| Case Report|| |
A 70-year-old female presented with asymptomatic thickened and yellowish lesions on the outer aspect of both the forearms for 10 years. She gave a history of goiter of 5 years duration for which partial thyroidectomy was done 14 years back followed by supplementation of 100 μgm of thyroxine daily. Since then, the patient continued to take thyroxine without further monitoring of her thyroid status. She did not give any history of reduced sweating or palpitations. There was no evidence of exophthalmos, no tachycardia, or tremors. Examination revealed ill-defined yellowish plaques on the extensors of both the forearms. There was prominence of hair follicles on the plaque giving a peau d'orange appearance [Figure 1] and [Figure 2]. Similar changes were not seen on the lower limbs [Figure 3]. The scalp hair and eyebrows showed no thinning. The systemic examination was unremarkable.
|Figure 1: Indurated plaques having peau de'orange appearance on extensors of forearms|
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A blood examination revealed low levels of thyroid stimulating hormone (TSH) (0.015 μIU/ml), with high levels of T4 (69.3 μg/dl) and T3 (39.2 ng/ml). The ECHO and ECG were normal. Other parameters were within normal limits.
A skin biopsy showed no significant changes in epidermis. Extensive mucin deposit with splaying of collagen bundles was seen in the dermis with empty spaces in between, with prominent deposits around the hair follicles [Figure 4] and [Figure 5]. These deposits showed staining with Alcian blue consistent with a diagnosis of myxedema [Figure 6].
|Figure 4: Histopathology shows mucin deposits with splaying of collagen bundles in the dermis [hematoxylin and eosin (H and E), ×400]|
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|Figure 6: Mucin deposits highlighted by Alcian blue stain (Alcian blue, ×400)|
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| Discussion|| |
Localized myxedema, or thyroid dermopathy, is characterized by localized thickening of the skin with a yellow waxy appearance. It is said to occur in 1–4% of patients with hyperthyroidism but may also develop after its correction. Localized hypertrichosis is often seen and the hair follicles may become indented causing a “peau d'orange” appearance. It is most commonly located in the pretibial area, and therefore often referred to as PTM. It has been also rarely reported in other areas such as the face, shoulders, arms, and abdomen.,
The differential diagnosis include Lichen myxedematosus and scleromyxedema. Lichen myxedematosus is characterized by eruption of asymptomatic soft papules which occur in groups, most commonly on face and arms and histopathologically differentiated from localized myxedema by circumscribed mucin deposits with increase in fibroblasts and collagen.
In scleromyxedema, there is diffuse thickening of skin with erythema along with generalized eruption of papules as in lichen myxedematosus, and histopathologically, similar to lichen myxedematosus with more extensive proliferation of fibroblasts.
Our patient presented with thickened plaques on the outer aspect of the upper limbs with sparing of the lower limbs suggestive of preradial myxedema. Preradial myxedema is a rare entity with only few cases reported in the literature.,,
In myxedema, anti-TSH receptor antibodies stimulate the TSH receptors in dermal fibroblasts to produce mucin and cause cutaneous lesions. In our patient, the antibody levels could not be assessed due to financial constraints. Most patients with PTM have a history of Graves' hyperthyroidism, but a small number of patients, as in our case, may present without any features of Graves' disease. There are also some case reports with hypothyroid or euthyroid and who subsequently become hyperthyroid. Hyperthyroidism is caused by many diseases that include Graves' disease, thyroiditis, toxic multinodular goiter, toxic adenomas, iodine-induced, functioning pituitary adenoma, factitial hyperthyroidism which is caused by exogenous intake of thyroid hormones as in our patient.
In our patient the cause of hyperthyroidism that led to the development of myxedema can be attributed to the long-term intake of thyroxine.
| Conclusion|| |
Preradial myxedema is a rare entity with few case reports in the literature. We could not find any other case report of exogenous thyroxine-induced preradial myxedema even after doing a thorough literature search. Patients who are on long-term thyroxine should be monitored regularly for any skin lesions suggestive of preradial or PTM and if present, confirmed with a biopsy to rule other disorders such as lichen myxedematosus and scleromyxedema.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]