Smooth muscle hamartoma of the lungs in a Wistar Hannover rat.

Hamartomas are tumor-like masses comprising disorganized normal tissue elements. To date, spontaneous hamartomas have been reported in several organs and tissues in rodents but not in the lungs. Here, we report the first case of a hamartoma in the lungs of a 108-week-old female Wistar Hannover rat. Grossly, a white spot, 7 mm in diameter, was observed on the costal surface of the left lung. Histopathologically, the nodular lesions adjacent to the bronchioles comprised mature smooth muscle cells. The lesion was not encapsulated and spread along the alveolar walls and ducts without compression of the surrounding tissue. In the nodules, elastic fibers enclosed small lumens lined with factor VIII-related antigen-positive endothelial cells. This structure suggested that the nodule mimicked an artery. Moreover, structural abnormalities were observed within the bronchioles and arterioles owing to the increased number of smooth muscle cells in the surrounding tissues. These features suggested that this was a case of tissue malformation rather than a neoplasm, leading to the diagnosis of a smooth muscle hamartoma of the lung.

Acquired smooth muscle hamartoma with sebaceous component.

BACKGROUND: Acquired smooth muscle hamartoma (ASMH) is a rare benign lesion characterized clinically by hyperpigmented plaques with hypertrichosis and some follicular papules. The main histologic finding is the presence of disorganized smooth muscle bundles in the dermis. Only 25 cases of ASMH have been reported in the literature. CLINICAL CASE: We present the case of an 18-year-old male who reported a pigmented area and increased hair growth on the left hemifacial with one year of evolution. Clinically, a plaque was observed in the preauricular region and on the left cheek with a linear Blaschkoid path, consisting of hyperpigmentation, hypertrichosis, and some papular lesions, with negative pseudo-Darier sign. Histological analysis showed an increase in the number of smooth muscle bundles in the middle and deep dermis surrounding abundant sebaceous glands and numerous hair follicles in different stages of evolution. CONCLUSIONS: The sebaceous component in this lesion was prominent. Therefore, we considered this lesion part of a spectrum where the acquired smooth muscle hamartoma and folliculosebaceous cystic hamartoma are found at the extremes. This case would fall in the middle of the range, as it combines both histological features.

INTRODUCCIÓN: El hamartoma de músculo liso adquirido (HMLA) es una lesión benigna adquirida, poco frecuente, caracterizada clínicamente por presentar placas hiperpigmentadas, con hipertricosis y algunas pápulas foliculares. El principal hallazgo histológico es la presencia de abundantes haces de músculo liso desorganizados en la dermis. Se han reportado solo 25 casos de HMLA en la literatura. CASO CLÍNICO: Se presenta el caso de un paciente de sexo masculino de 18 años que refirió una zona pigmentada y el aumento de vello en la hemicara izquierda con un año de evolución. Clínicamente se observó una placa en la región preauricular y mejilla izquierda con trayecto lineal blaschkoide, constituida por hiperpigmentación, hipertricosis y algunas lesiones papulares, con signo pseudo-Darier negativo. Histológicamente se encontró un aumento en el número de haces de músculo liso en la dermis media y profunda rodeando abundantes glándulas sebáceas, así como numerosos folículos pilosos en diferentes estadios de evolución. CONCLUSIONES: El componente sebáceo en esta lesión fue muy marcado, por lo que se considera que forma parte de un espectro donde en los extremos se encuentran el hamartoma de músculo liso adquirido y el hamartoma quístico folículo sebáceo. El presente caso se encontraría en medio, ya que combina ambas características histológicas.

Acquired smooth muscle hamartoma with sebaceous component / Hamartoma de músculo liso adquirido con componente sebáceo

Abstract Background: Acquired smooth muscle hamartoma (ASMH) is a rare benign lesion characterized clinically by hyperpigmented plaques with hypertrichosis and some follicular papules. The main histologic finding is the presence of disorganized smooth muscle bundles in the dermis. Only 25 cases of ASMH have been reported in the literature. Clinical case: We present the case of an 18-year-old male who reported a pigmented area and increased hair growth on the left hemifacial with one year of evolution. Clinically, a plaque was observed in the preauricular region and on the left cheek with a linear Blaschkoid path, consisting of hyperpigmentation, hypertrichosis, and some papular lesions, with negative pseudo-Darier sign. Histological analysis showed an increase in the number of smooth muscle bundles in the middle and deep dermis surrounding abundant sebaceous glands and numerous hair follicles in different stages of evolution. Conclusions: The sebaceous component in this lesion was prominent. Therefore, we considered this lesion part of a spectrum where the acquired smooth muscle hamartoma and folliculosebaceous cystic hamartoma are found at the extremes. This case would fall in the middle of the range, as it combines both histological features.

Resumen Introducción: El hamartoma de músculo liso adquirido (HMLA) es una lesión benigna adquirida, poco frecuente, caracterizada clínicamente por presentar placas hiperpigmentadas, con hipertricosis y algunas pápulas foliculares. El principal hallazgo histológico es la presencia de abundantes haces de músculo liso desorganizados en la dermis. Se han reportado solo 25 casos de HMLA en la literatura. Caso clínico: Se presenta el caso de un paciente de sexo masculino de 18 años que refirió una zona pigmentada y el aumento de vello en la hemicara izquierda con un año de evolución. Clínicamente se observó una placa en la región preauricular y mejilla izquierda con trayecto lineal blaschkoide, constituida por hiperpigmentación, hipertricosis y algunas lesiones papulares, con signo pseudo-Darier negativo. Histológicamente se encontró un aumento en el número de haces de músculo liso en la dermis media y profunda rodeando abundantes glándulas sebáceas, así como numerosos folículos pilosos en diferentes estadios de evolución. Conclusiones: El componente sebáceo en esta lesión fue muy marcado, por lo que se considera que forma parte de un espectro donde en los extremos se encuentran el hamartoma de músculo liso adquirido y el hamartoma quístico folículo sebáceo. El presente caso se encontraría en medio, ya que combina ambas características histológicas.

Bilateral Nipple Enlargement as a Secondary Effect of Anabolic Drugs: A Histopathological Mimicker of Smooth Muscle Hamartoma.

Smooth muscle hamartoma are usually solitary and congenital, may affect the genital area and nipples. Histopathologically, they are characterized by the presence of mature smooth muscle bundles. We present a 40 year-old male with bilateral nipple enlargement excised with clinical suspicion of bilateral leiomyoma. Skin biopsy shows mature, irregularly arranged smooth muscle bundles and lactiferous ducts between them. Immunohistochemistry is positive for smooth muscle actin, desmin and fumarase, but negative for estrogen and progestogen receptors. The presence of lactiferous ducts excludes bilateral leiomyomas. Even when, histopathologically, this can be interpreted as the nipple-type of muscular hamartoma of the breast, clinical history favors an anabolic drug-induced lesion. Bodybuilders present gynecomastia and nipple enlargement as frequent problems, but we have not found any histopathological description of these nipple lesions. We consider that dermatologists should be aware of the presence of them and dermatopathologists should know their histopathological features to avoid misdiagnosis as neoplasms.

Smooth muscle hamartoma and striated muscle hamartoma: Clinicopathologic characterization of two rare entities and literature review.

Smooth muscle hamartoma (SMH) and striated muscle hamartoma (STH) are anomalous proliferations of smooth muscle or striated muscle, respectively, in anatomic sites where these tissues are normally present. To date, only limited cases have been reported describing these lesions. In this study, we sought to characterize the clinicopathologic features of both SMH and STH. A total of 27 cases of SMH and 12 cases of STH from 1990 to 2020 were identified. SMH cases had a slight male predominance (63%) and a mean age of presentation of 20 years (range: 4 months-91 years), with a mean size of 9.3 mm (±13.3). In contrast, STH were equally distributed in gender, with a mean age of presentation of 40 years (range: 3 months-66 years) and a mean size of 5.7 mm (±3.6). SMH were more commonly located in the torso and extremities (70%) and STH in the head and neck area (92%). One case of SMH recurred after 1.1 years and in the initial diagnosis the lesion was present at the tissue edge. None of the cases of STH had a recurrence. We present the largest cohort of SMH and STH, and report the first case of a recurrent SMH, suggesting the importance of obtaining a clean margin for these lesions.

Post-zygotic ACTB mutations underlie congenital smooth muscle hamartomas.

BACKGROUND: Congenital smooth muscle hamartomas (CSMHs) are benign lesions that share clinical and histopathological features with Becker nevus, a mosaic disorder associated with post-zygotic ACTB mutations. Given the clinical and histopathological overlap between CSMH and Becker nevus, we hypothesized that post-zygotic mutations in ACTB may underlie CSMH. METHODS: Direct sequencing of ACTB gene in affected and unaffected tissue isolated from one case of hemihypertrichosis and hemihypertrophy corresponding to giant segmental CSMH and hemihypertrophy. This was followed by direct sequencing with and without enrichment assay for hotspot ACTB mutations in affected tissue from 12 samples of isolated CSMH from unrelated individuals. RESULTS: In total we identified somatic missense ACTB mutations in 9 out of 13 CSMHs (69%). Mutations were either novel or previously reported in Becker nevi and Becker nevus syndrome. CONCLUSIONS: CSMHs result from post-zygotic ACTB mutations. This study proves that CSMHs and Becker nevi are nosologically related, and expand the phenotypic spectrum of ACTB mutations.

Laser treatment of epidermal nevi: A multicenter retrospective study with long-term follow-up.

BACKGROUND: Patients with epidermal nevi strongly demand cosmetic improvement. Laser treatment appears appealing and is frequently used in clinical practice. Nevertheless, large series with long-term follow-up are missing, preventing definitive conclusions about its real benefit. OBJECTIVE: To evaluate the long-term effectiveness and safety of lasers for epidermal nevi. METHODS: Bicentric, retrospective, cohort study, including all patients treated with a laser for an epidermal nevus with more than a 1-year follow-up. RESULTS: Seventy patients were treated for different types of epidermal nevi, mostly with ablative lasers: 23 verrucous epidermal nevi, 16 nevi sebaceous, 26 Becker nevi, 2 inflammatory linear verrucous epidermal nevi, 1 smooth-muscle hamartoma, 1 rounded and velvety epidermal nevus, and 1 nevus lipomatosus superficialis. The follow-up period was a median of 37 months (range, 12-127 months). Better results, fewer recurrences, and higher patient satisfaction were noted in treatments for verrucous epidermal nevi than for nevi sebaceous. Q-switched lasers failed to show any degree of improvement in almost all patients with Becker nevus. LIMITATIONS: The retrospective nature of the study. CONCLUSIONS: Ablative lasers can treat verrucous epidermal nevi with good long-term esthetic results but have limited long-term efficacy for nevus sebaceous. Q-switched lasers failed to improve Becker nevi.

Dermoscopic findings of a congenital smooth muscle hamartoma in an infant.

Cutaneous smooth muscle hamartoma is an uncommon, benign tumor developing in the dermis as a result of disorganized hyperproliferation of arrector pili muscle fibers. We present a 1-month-old infant with a congenital smooth muscle hamartoma together with the dermoscopic findings of the case. Dermoscopy can be a helpful non-invasive tool in diagnosing congenital smooth muscle hamartoma due to its distinct findings that help to differentiate it from close mimickers like solitary mastocytoma.

Terminal osseous dysplasia with pigmentary defects (TODPD) in a Turkish girl with new skin findings.

Terminal osseous dysplasia with pigmentary defects (TODPD; MIM #300244) is an extremely rare, X-linked dominant, in utero male-lethal disease, characterized by skeletal dysplasia of the limbs, pigmentary defects of the skin, and recurrent digital fibromatosis of childhood. Delayed/abnormal ossification of bones of the hands and feet, joint contractures, and dysmorphic facial features may accompany. A single recurrent mutation (c.5217 G>A) of the FLNA gene which causes cryptic splicing was identified as the cause of the disease. We here present the first TODPD case from Turkey with full-blown phenotype who exhibit unique additional findings, hypopigmented patch on the lower extremity following Blaschko's lines and smooth muscle hamartoma of the scalp in review of all the previously reported TODPD cases.

Multiple acquired smooth muscle hamartomas with thick-walled blood vessels on scalp.

Smooth muscle hamartoma (SMH) is a benign hamartomatous condition that consists of a dermal proliferation of smooth muscle cells. We hereby report a case of multiple, acquired SMHs on scalp. A 25-year-old male had a 6-year history of multiple, asymptomatic, hyperpigmented plaques on the scalp which were progressively increasing in number and size. Histopathological examination revealed large thick-walled blood vessels, in addition to the haphazardly arranged discrete smooth muscle bundles in the reticular dermis. This case of SMH is unusual in being acquired, having multiple lesions, involving scalp, and having thick-walled blood vessels apart from arrector pili muscle bundles. It emphasizes the wide spectrum of clinical and histopathological variations that may be associated with acquired SMH.

Hamartoma mioide, serie de casos y revisión de la literatura / Myoid hamartoma: a case series and literature review

Abstract: Myoid hamartoma is a rare entity, and was first described by Davies and Riddell in 1973. It is pathologically defined as the mixture of fatty glandular tissue and fibrous connective tissue, associated with a widespread focus of fusiform muscle cells. Six cases of HM diagnosed in seven patients are presented, with emphasis on imaging findings and characteristics of their respective core biopsies. The importance of biopsy in these lesions is required to differentiate malignant diseases. There is no need for excisional biopsy, because this is not associated with high-risk lesions or carcinomas.

Resumen: El hamartoma mioide es una lesión infrecuente; fue descrita por primera vez por Davies y Riddell en el año 1973; se define histológicamente como la mezcla de tejido glandular adiposo y conjuntivo fibroso, asociado a extensos focos de células musculares fusiformes. Se presentan 7 casos de HM diagnosticados en 7 pacientes, haciendo énfasis en las características imagenológicas y los hallazgos de las respectivas biopsias core. La importancia de realizar biopsia en estas lesiones radica en la necesidad de diferenciarla de patologías malignas; así mismo no existe necesidad de biopsia excisional, ya que se trata de una entidad que no se asocia a lesiones de alto riesgo o con cáncer.

Combined cutaneous smooth muscle hamartoma and nevus flammeus.

We report on a combined cutaneous smooth muscle hamartoma and reticulate port-wine stain on the thigh of a 26-year-old woman. The lesion measured 30 cm in longest diameter and presented clinically with a macular erythematous telangiectatic vascular appearance. It was focally ulcerated, which represented the patient's main complaint. Histopathological study demonstrated smooth muscle bundles closely intermingled with a vascular component comprised of capillaries and venules. Such a morphological presentation is, to the best of our knowledge, unique in the literature.

Congenital Smooth Muscle Hamartoma with Follicular Spotted Appearance / 대한피부과학회지

A congenital smooth muscle hamartoma is a rare benign cutaneous abnormality and histologically characterized by smooth muscle hyperplasia with a great number of long and straight bundles of smooth muscle at various angles of the orientation, throughout the dermis. A congenital smooth muscle hamartoma usually presents as a congenital hairy patch or plaque with or without hyperpigmentation on the trunk or extremities. The congenital smooth muscle hamartoma with follicular spotted appearance is a rare clinical variant, and is appeared as a patch with marked follicular papules. Herein, we report a 16-year-old girl with this rare patch follicular variant of congenital smooth muscle hamartoma, on the left upper arm.

Multiple smooth muscle hamartoma: case report and review of the literature.

Smooth muscle hamartoma (SMH) is a proliferative disorder of cells originating from muscle cells. It is a benign tumoral mass that usually presents as a single congenital skin-colored and hypertrichotic plaque involving the trunk and extremities. Multiple SMHs have rarely been reported in the literature. We describe the case of a seven-month-old girl with multiple SMHs located over the back and arm areas. The diagnosis was confirmed by biopsy and immunohistochemical (IHC) staining. She had no cerebral or skeletal abnormalities and her growth and development were normal.

A case of acquired smooth muscle hamartoma on the sole.

A smooth muscle hamartoma is a benign proliferation of smooth muscle bundles within the dermis. It arises from smooth muscle cells that are located in arrector pili muscles, dartos muscles, vascular smooth muscles, muscularis mammillae and the areolae. Acquired smooth muscle hamartoma (ASMH) is rare, with only 10 such cases having been reported in the English medical literature to date. Most of these cases of ASMH were shown to have originated from arrector pili and dartos muscles. Only one case was reported to have originated from vascular smooth muscle cells. A 21 year-old woman presented with a tender pigmented nodule, with numbness, on the sole of her foot, and this lesion had developed over the previous 18 months. The lesion showed no hyperpigmentation or hypertrichosis, and the biopsies demonstrated increased smooth muscle bundles in the dermis, and especially around the blood vessels. Moreover, the specimens stained positive with Masson trichrome stain and alpha-smooth-muscle actin antibodies, thus supporting our diagnosis of ASMH of the foot sole. Herein, we report on a rare case of ASMH on the foot sole, and this lesion originated from vascular smooth muscle cells. This type of case has not been previously described in the English medical literature.

A Case of Acquired Smooth Muscle Hamartoma on the Sole

A smooth muscle hamartoma is a benign proliferation of smooth muscle bundles within the dermis. It arises from smooth muscle cells that are located in arrector pili muscles, dartos muscles, vascular smooth muscles, muscularis mammillae and the areolae. Acquired smooth muscle hamartoma (ASMH) is rare, with only 10 such cases having been reported in the English medical literature to date. Most of these cases of ASMH were shown to have originated from arrector pili and dartos muscles. Only one case was reported to have originated from vascular smooth muscle cells. A 21 year-old woman presented with a tender pigmented nodule, with numbness, on the sole of her foot, and this lesion had developed over the previous 18 months. The lesion showed no hyperpigmentation or hypertrichosis, and the biopsies demonstrated increased smooth muscle bundles in the dermis, and especially around the blood vessels. Moreover, the specimens stained positive with Masson trichrome stain and alpha-smooth-muscle actin antibodies, thus supporting our diagnosis of ASMH of the foot sole. Herein, we report on a rare case of ASMH on the foot sole, and this lesion originated from vascular smooth muscle cells. This type of case has not been previously described in the English medical literature.

A Case of Congenital Smooth Muscle Hamartoma Presenting as a Human Tail / 대한피부과학회지

A human tail is a rare congenital anomaly, and is characterised by a prominent lesion from the lumbosacrococcygeal region. Human tails are classified into 'true tails' and 'pseudotails'. True tails are comprised of only mesenchymal tissue. They are presumed to be remnants of the embryologic tail. All other lumbosacrococcygeal protrusions are summarized as pseudotails. Congenital smooth muscle hamartoma usually presents as a well-circumscribed, hypertrichotic, hyperpigmented or skin-colored patch or plaque on the trunk or an extremity at birth. Histologically, numerous thick, long, well-defined bundles of smooth muscle fibers are scattered throughout the dermis in various directions. We report a case of congenital smooth muscle hamartoma in a 15-year-old male patient who presented with a tail-like protruding mass accompanied by hypertrichosis and underlying soft tissue deviation.