Bilateral Multisegmental Zosteriform Leiomyoma Cutis: A Rare Entity.

Cutaneous leiomyomas are benign tumors derived from the smooth muscles of the skin. They are firm, skin-colored to brownish, frequently painful papules and nodules presenting either as a solitary tumor or multiple clustered lesions. Uncommon patterns of multiple leiomyoma cutis include linear, zosteriform, or dermatomal-like arrangement of lesions. We saw a 32-year-old man who presented with clusters of skin colored to reddish brown, occasionally painful papules and nodules distributed segmentally over C6 to T8 dermatomes on left side and T11 to L1 dermatomes on right side. Histopathology confirmed the diagnosis of cutaneous leiomyoma. The case is reported here for the occurrence of this benign cutaneous neoplasm in an extremely rare bilateral multisegmental distribution.

What was known?

Leiomyoma cutis are benign cutaneous neoplasms derived from smooth muscles of the skin that may be solitary or may occur as clusters of papules often distributed in a segmental fashion.

Introduction

Cutaneous leiomyomas are benign tumors with smooth muscle differentiation that arise from the arrector pili muscle, the muscular layer of the blood vessels, the tunica dartos, labia majora, or nipples. Three types are recognized, namely piloleiomyoma, dartoic leiomyoma, and angioleiomyoma; piloleiomyomas being the most common type.[1] Usually they appear between the first and third decades of life.[2] The lesions can be solitary or more commonly multiple. Multiple lesions may be arranged in diffuse (disseminated), blaschkoid, or segmental (zosteriform) patterns.[3] Patients with piloleiomyoma often complain of pain that may be spontaneous or secondary to cold, pressure, or emotion.[4] We present here a case of bilateral multisegmental leiomyoma cutis because of the unusual presentation.

Case Report

A 32-year-old man presented with multiple brownish solid elevations of the skin over the back present for the preceding 6 years. First appearing on the left side of the lower back, new lesions sequentially developed over the upper back on the same side and lower back on the opposite side. The lesions had however remained stationary for the last one year. Occasional mild pain on exposure to cold was complained of. History of hematuria, lower back pain, abdominal swelling or heaviness was absent. There was no family history of similar lesions and the patient was otherwise in good health. Clinical examination revealed skin colored to brownish papules and nodules of varying sizes, ranging from 2 mm to 2 cm, distributed over multiple dermatomes strictly respecting the midline. On the left side C6 to T8 dermatomes and on the right side T11 to L1 dermatomes were involved [Figure 1]. Most papules were discrete whereas some had coalesced to form plaques [Figure 2]. There were no other mucocutaneous findings and systemic examination revealed no abnormality. Routine hematological and biochemical investigations and ultrasonography of whole abdomen were normal. Histopathological examination with hematoxylin and eosin staining revealed poorly demarcated interlacing bundles of smooth muscle fibers intermingled with varying amount of collagen under low power magnification [Figure 3]. The muscle fibers contain centrally located, thin, blunt edged nuclei [Figure 4]. Special stains and genetic studies could not be performed owing to local unavailability and financial constraints. Based on the distinct clinical and histopathologic findings, a diagnosis of sporadic multisegmental zosteriform leiomyoma cutis was given. The patient was counseled about his disease and therapeutic options were discussed. He refused to undergo any active intervention for his nearly asymptomatic condition and was kept under regular follow-up.

Figure 1

Clusters of papules and nodules in multisegmental distribution over the back

Figure 2

Close-up of left mid-back showing discrete and coalescing papules and nodules in a segmental distribution

Figure 3

Histopathology showing intertwined fascicles of smooth muscles occupying the upper and mid-dermis. H and E, ×100

Figure 4

Elongated nuclei of smooth muscles with rounded edges. H and E, ×400

Discussion

The most common type of presentation of leiomyoma cutis is that of multiple piloleiomyomas. Both solitary and multiple piloleiomyomas arise from the arrectores pilorum muscles and occur as grouped, linear, or segmentally distributed firm, red to brown intradermal papules and nodules, which are fixed to the skin, but free from the deeper tissues. The sites involved are the extensor aspect of the extremities, trunk, face and neck in decreasing order of frequency.[5]

Multiple piloleiomyomas may be inherited in an autosomal-dominant fashion and may be associated with uterine leiomyomas and aggressive renal carcinoma, also known as multiple cutaneous and uterine leiomyomatosis (MCUL) or Reed's syndrome and hereditary leiomyomatosis and renal cell carcinoma (HLRCC), respectively.[3]

Two types of segmental manifestation of the autosomal dominantly inherited disease are postulated. The type 1 occurs due to heterozygosity for the underlying mutation with a clinical picture similar to that in a non-mosaic phenotype. In type 2, loss of heterozygosity causes homo- or hemizygosity, with a pronounced segmental manifestation of lesions.[67] Though the precise molecular mechanisms that lead to the development of multiple cutaneous leiomyomas are unknown, recent studies have demonstrated the mutation of a gene encoding fumarate hydratase, on chromosome 1q42.3-43 that predispose individuals to MCUL and HLRCC.[389] There was no family history of uterine or cutaneous leiomyoma in our patient, neither was there any finding suggestive of renal neoplasm affecting the patient himself. The clinical profile of our patient was suggestive of non-familial type 2 segmental leiomyoma.

Patients with piloleiomyoma often have pain that may be spontaneous or secondary to cold, pressure, or emotion. The precise pathomechanism of pain in leiomyoma cutis is unknown but pressure on nerve fibers and abnormal muscle contraction have been suggested as possible explanations.[10] Our patient was however nearly asymptomatic.

Histology of piloleiomyoma is characterized by poorly demarcated interlacing bundles of smooth muscle fibers with intermingling collagen fibers of varying amount under low power magnification. The muscle fibers are mostly straight, with little or no waviness and contain centrally located, thin, very long, blunt edged “eel-like” nuclei.[11]

Treatment of cutaneous leiomyoma depends on the number of lesions and the presence or absence of symptoms. Camouflage with cosmetics and avoidance of exposure to cold may be the only measures required. Surgical excision with skin grafting may be indicated for a small group of lesions. The condition may however recur, particularly in patients with multiple lesions. When lesions are painful, various pharmacologic agents such as nifedipine, phenoxybenzamine and other alpha-1 blockers and nitroglycerin may be tried alone or in combination.[1512] A recent report[13] described carbon dioxide laser ablation therapy of multiple cutaneous leiomyomas with continued pain relief 9 months after operation.

In conclusion, we presented here a case of multi-segmental zosteriform leiomyomas involving dermatomes of both sides. Though segmental distribution of leiomyoma is common, bilateral multi-segmental involvement is extremely rare, and after extensive PubMed search we could locate only one case report of piloleiomyomas showing bilateral multi-segmental distribution.[14] In view of the potential association with aggressive renal carcinoma, patients with multiple leiomyoma cutis should be kept under long-term follow up.

What is new?

Segmental distribution of leiomyoma is common. However, bilateral multi-segmental distribution is extremely rare and to the best of our knowledge, this is the second case report of sporadic cutaneous leiomyoma showing bilateral multi-segmental distribution.