Multiple Nodules on Hand, Elbow and Buttock

Case History, Examination, and Investigation Findings

A 65-year-old male presented with a 2-year history of multiple asymptomatic nodules involving his buttock, elbow, and hand. The nodules were gradually enlarging and increasing in number. There was no significant personal or family medical history of skin disorders, genetic conditions, or malignancies.

Physical examination revealed multiple well-demarcated, skin-colored nodules on his left palm and thumb [Figure 1]. Similar nodules were also present on the extensor aspect of his right elbow joint [Figure 2a] nd his left buttock near the gluteal cleft. The nodules were firm in consistency and painless on palpation. There were no other mucocutaneous manifestations, and the patient did not have any thyroid nodules or breast lumps. Incisional biopsy was performed and histopathological examination revealed a well-circumscribed dermal nodule comprising of banal spindle cells amidst hyalinized collagen bundles, arranged in a plywood pattern [Figure 3].

Figure 1.

Clinical view of numerous firm discrete skin-colored nodules involving the left palm and thumb

Figure 2.

Clinical view of a solitary firm discrete skin-colored nodule involving the right elbow

Figure 3.

Histopathology of nodule displaying proliferation of banal spindle cells amidst hyalinized collagen bundles, arranged in a plywood pattern. (hematoxylin and eosin, original magnification ×40)

Question

What is your diagnosis?

Answer

Multiple Sclerotic Fibromata

Discussion

Sclerotic fibroma is a rare, benign cutaneous tumor first reported by Weary et al.[1] It is a collagenous variant of fibroma and may appear on the skin and mucous membranes as firm papulonodules. Dermoscopically, it has been described to have a homogenous white background with peripheral arborizing vessels and an erythematous halo.[2] They are distinctive architecturally from other common dermal fibrotic nodules by the presence of sharp circumscription and a strikingly uniform storiform pattern. Factor 13a-positive fibroblasts may be demonstrated immunohistochemically.[3] It can present as a sporadic solitary tumor or in multiples whereby a diagnosis of Cowden syndrome should be of clinical suspicion. A literature review in 2017 revealed that all cases of reported multiple sclerotic fibroma have been associated with Cowden syndrome.[4]

Cowden syndrome is a PTEN hamartoma tumor syndrome that predisposes individuals to malignancies, most commonly of thyroid or breast origin. In addition to sclerotic fibroma, other pathognomonic cutaneous lesions that are part of Cowden syndrome's major diagnostic criteria are multiple trichilemmomas, acral keratosis, and oral papillomas.[5]

The patient had no other cutaneous features of Cowden syndrome and an extensive workup for extracutaneous features of the disease, including malignancies, returned negative. Although disease manifestations of Cowden syndrome occur over time, 99% of mucocutaneous manifestations appear by the third decade of life.[6] In addition, extracutaneous manifestations of Cowden syndrome tend to present by the age of 50.[4,7] The age of this patient and the lack of any other manifestations suggestive of Cowden's syndrome make this diagnosis unlikely. We believe this to be the first reported case of isolated multiple sclerotic fibromata not associated with Cowden syndrome.

Sclerotic fibromata are benign tumors that require no treatment. However, the tumors may be surgically excised if patients find them cosmetically unacceptable, or if they impair function.

The differential diagnoses for patients presenting with multiple firm nodules on the hand or elbow include rheumatoid nodules, gouty tophi, fibromatosis, and erythema elevatum diutinum (EED). EED is a rare form of cutaneous vasculitis with a strong clinicohistopathologic resemblance to sclerotic fibroma. Similar to the patient's presentation, EED is characteristically distributed on the hands and extensor surfaces of joints. It may be differentiated from sclerotic fibroma histologically by the presence of leukocytoclastic vasculitis, but this is sometimes difficult, especially in late-stage EED, where features of vasculitis may be absent.[8]

Learning points

1. Sclerotic fibroma is a rare, benign cutaneous tumor.

2. It can occur as a sporadic solitary tumor or in multiples whereby a diagnosis of Cowden syndrome should be of clinical suspicion.

3. Histopathologically, it is characterized by a well-circumscribed nodule comprising of spindle cells amidst hyalinized collagen bundles.

4. Clinically, it can be misdiagnosed as rheumatoid nodules, gouty tophi, and fibromatosis.

5. Clinicians should ensure a thorough workup for Cowden syndrome is done in patients who present with multiple sclerotic fibromata.

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Conflicts of interest

There are no conflicts of interest.