Combined Melanocytic Nevus and Nevus Sebaceus: A Case Series and Review of the Literature.

ABSTRACT: Nevus sebaceus is a rare congenital hamartoma with clinical and histopathological features that change with puberty. It has been associated with a number of secondary neoplasms, most of which are thought to derive from follicular germ cells. In this article, the authors describe a total of 3 cases of combined melanocytic nevus and nevus sebaceus to highlight this rare finding.

Morphologic Spectrum of Rhabdomyomatous Mesenchymal Hamartomas (Striated Muscle Hamartomas) in Pediatric Dermatopathology.

BACKGROUND: Rhabdomyomatous mesenchymal hamartomas (RMHs), also termed striated muscle hamartomas, are rare benign tumors of skin and subcutis, which mostly occur at birth with a predilection for the head and neck. Simple surgical excision is the treatment modality of choice with excellent prognosis. OBJECTIVE: To review the spectrum of the different clinical and pathologic features of RMHs in pediatric patients and recognize their characteristics to avoid confusion with other lesions in their list of differential diagnosis. METHODS: Six cases of RMH diagnosed at our institution from 2009 to 2021 were retrieved from our files and reviewed retrospectively after anonymization by an honest broker. This review is IRB-approved by the University of Pittsburgh School of Medicine, study STUDY19080192. RESULTS: The patients' age ranged from 6 days to 8 years, with a female predominance (2:1). In all cases, the lesion was present at birth. All lesions, except for 2, occurred in the head and neck regions. One patient had multiple additional small nodules in the face, whereas all others presented with solitary RMHs. The size of the lesions varied, and their composition included bundles of skeletal muscle (the landmark finding) associated with variable amounts of adipose, fibrous, vascular, nerve, and adnexal structures. CONCLUSIONS: RMH is a benign hamartomatous lesion with a variable phenotypic spectrum. RMHs predominate in the head and neck. Familiarity with these lesions, including their presentation in less frequent anatomical sites, is important to avoid diagnostic misinterpretations and potential overtreatment. This study represents one of the largest series of RMHs in the literature, including an unusual case in a perianal location.

Cutaneous Cephalic Neurocristic Hamartoma on the Head With Melanocytic, Cartilage, Blood Vessel, Neural, and Bony Tissue.

ABSTRACT: We report on a congenital tumor of the face and scalp in a male newborn, histologically proven to contain melanocytes, cartilage, and bone, vascular, and neural tissue as part of a pigmented congenital tumor. Thus, this tumor was classified as a cutaneous cephalic neurocristic hamartoma.

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.

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.

Congenital Oral Masses: An Anatomic Approach to Diagnosis.

Although congenital oral masses are rare, they are readily detectable during fetal US screening. Most congenital oral masses are benign, but some may cause mechanical airway obstruction, resulting in poor outcomes at delivery. The radiologist's ability to describe these abnormalities and their physiologic sequelae accurately can have a substantial effect on perinatal treatment. Furthermore, despite being rare, congenital oral lesions encountered at screening and at follow up fetal MRI provide the opportunity to make a specific diagnosis by following a simple anatomic approach. This article describes an anatomic algorithm as the framework for accurate diagnosis of congenital oral lesions. The imaging appearance of the most common congenital oral cavity neoplasms is outlined, including vascular anomalies, epulides, choristomas, congenital lingual thyroid anomalies, lingual hamartomas, and epignathi, and other conditions that mimic these at US. Also reviewed are perinatal management of masses that affect the fetal airway and the imaging features key to optimizing delivery outcomes. Online supplemental material is available for this article. ©RSNA, 2019.

Precalcaneal congenital fibrolipomatous hamartoma: Rare or under-reported?

Precalcaneal congenital fibrolipomatous hamartoma (PCFH) is a benign under-reported condition of infancy characterized by the presence of soft nodules on precalcaneal plantar surface of the heel. These lesions are usually bilateral solitary and asymptomatic. We present a 2-month-old infant with solitary skin-colored nodules present on precalcaneal plantar aspect of bilateral heels.

Congenital eccrine angiomatous hamartoma: Expanding the morphologic presentation and a review of the literature.

Eccrine angiomatous hamartoma (EAH) is a rare benign vascular hamartoma characterized histologically by an increased size and number of mature eccrine glands associated with multiple foci of dilated capillaries in the dermis and subcutis. EAH typically presents in children as discrete, solitary nodules, or plaques most commonly located on the extremities. Some cases of EAH have an agminated distribution involving classic locations, or present as solitary lesions in less common locations such as the face, scalp, or trunk. We report the case of congenital EAH in a child with atypical morphological features and pattern of distribution further expanding on the range of presentations classically described.

Medallion-like dermal dendrocyte hamartoma: A rare congenital CD34-positive dermal lesion clinically and pathologically overlapping with fibroblastic connective tissue nevus.

Both medallion-like dermal dendrocyte hamartoma and fibroblastic connective tissue nevus are rare benign dermal lesions composed of CD34-positive spindle cells. Although regarded as different diseases, it is sometimes difficult to distinguish between them due to their clinical and pathological similarities. We present a case of medallion-like dermal dendrocyte hamartoma that could also be diagnosed as fibroblastic connective tissue nevus and propose the possibility of overlap in these diseases.

Tailgut cyst: report of three cases and review of the literature.

INTRODUCTION: Tailgut cysts or retrorectal cystic hamartomas are congenital developmental lesions which are often misdiagnosed due to their rare incidence, anatomical position and variable clinical presentation. CASE REPORT: We report three clinical cases: one of a 67-year old woman with high fever and anal bulging; the second case was a 50-year old woman with diffuse abdominal pain and the third case was a 52-year old woman with high fever and no abdominal or rectal pain. The rectal examination and MRI indicated the presence of a tailgut cyst. In all the cases a complete resection through a posterior perineal route was performed. Histopathological examination confirmed the diagnosis of a tailgut cyst, with a malignant component identified in the third case. DISCUSSION: The discussion presents a brief review of the relevant information described in the literature to highlight the cornerstones for appropriate diagnosis and treatment of a tailgut cyst. Tailgut cysts are to be considered in the differential diagnosis of retrorectal or presacral masses as malignant transformation can occur.

Rare congenital meningothelial hamartoma of the scalp with progressive growth.

Scalp lesions are common pediatric findings that present for neurosurgical evaluation and management. The majority will be benign. Meningothelial hamartomas represent a rare subset of congenital cutaneous lesions with the potential for intracranial extension and microscopic infiltration of the surrounding tissues. The authors report in this paper a case of meningothelial hamartoma of the scalp that demonstrated serial growth and invasion of the scalp. The degree of microscopic involvement and growth necessitated close follow-up and repeat excision.

Cutaneous fibrolipomatous hamartoma: Report of 2 cases with retrocalcaneal location.

Precalcaneal congenital fibrolipomatous hamartoma is an underreported benign entity that has been described in the literature under different names. We present two cases of unilateral fibrolipomatous hamartoma (FLH) appearing in a unique location: on the posterior aspect of the foot overlying the heel. We propose the term "FLH of the skin" as a more inclusive and less confusing term for this condition, thus allowing distinction with FLH arising from neural tissue. High-frequency ultrasonography appears to be a useful diagnostic tool that may avoid unnecessary biopsies for this condition.

[Congenital Simple Hamartoma of the Retinal Pigment Epithelium]. / Kongenitales einfaches Hamartom des retinalen Pigmentepithels.

BACKGROUND: Congenital simple hamartoma of the retinal pigment epithelium (CSHRPE) is an uncommon benign lesion with characteristic clinical features. Ophthalmoscopically it appears as a small localized, well circumscribed, pigmented tumor in the foveal region. In contrast to the more common flat congenital hypertrophy of the RPE the CSHRPE has an elevated nodular appearance. PATIENTS AND METHODS: Retrospective case series of three patients with CSHRPE. Clinical morphological features using different imaging techniques are presented. RESULTS: A typical dark lesion was incidentally noted in the macula of two patients. Optical coherence tomography (OCT) demonstrated a nodular preretinal hyperreflectivity with shadowing of deeper structures. In one patient the CSHRPE was hypofluorescent throughout the angiogram. The third patient presented with a reduced visual acuity of 0.3. A characteristic lesion was found at the foveal center. OCT revealed a hyperreflective preretinal lesion with associated moderate disruption of the foveal architecture. Amblyopia treatment slightly improved visual acuity in this case. The lesions remained stationary in two patients (follow-up 8 - 14 months). CONCLUSIONS: CSHRPE are usually detected as an incidental finding. Given its benign character and typically asymptomatic presentation an observational treatment approach is generally recommended. The lesions generally remain stationary and are not known to grow. In cases with visual impairment due to foveal involvement amblyopia treatment should be initiated.

Precalcaneal congenital fibrolipomatous hamartoma.

Precalcaneal congenital fibrolipomatous hamartoma is a benign condition of infancy that is sometimes misdiagnosed due to lack of reports in the literature. Lesions usually present with painless, non-pruritic, skin colored bilateral, solitary, symmetric nodules located in the middle of the heels. The lesions gradually increase in size and then regress by the age of 2 to3 years old.

Full-thickness macular hole associated with congenital simple hamartoma of retinal pigment epithelium (CSHRPE).

PURPOSE: To report a unique case of congenital simple hamartoma of retinal pigment epithelium (CSHRPE) associated with full-thickness macular hole (FTMH). METHODS: A 14-year-old female with a previous diagnosis of simple hamartoma of retinal pigment epithelium in the left eye presented with a 3-week onset of reduced visual acuity in the same eye. Complete ophthalmological examination with spectral domain ocular coherence tomography (SD-OCT) and autofluorescence imaging was carried out. Results were compared with the last 4-year follow-up data. RESULTS: On examination, visual acuity in the left eye was counting fingers compared to 20/100 documented in the last follow-up. Fundoscopy revealed a nodular, heavily pigmented, circumscribed foveal mass, with 0.5 mm basal diameter and 1.1 mm thickness corresponding to the simple RPE hamartoma. Although the latter remained unchanged throughout the follow-up period, a new lesion at the inferior edge of the hamartoma was noted. SD-OCT confirmed the presence of a FTMH with no evidence of associated epiretinal membrane, vitreomacular traction or posterior vitreous detachment. After explaining the risks and benefits of vitrectomy for FTMH, the patient declined surgery. CONCLUSIONS: CSHRPE may have associated features such as feeding vessels, retinal surface wrinkling, pigmented vitreous cells, retinal exudation and vitreoretinal adhesion. The case presented herein broadens the clinical spectrum of CSHRPE and emphasizes that despite the benign nature of the lesion, which remains stable without growth, visual loss may occur, attributable to foveal traction and development of FTMH. We postulate that protrusion of the tumor into the vitreous cavity results in tissue stretching and development of anteroposterior and tangential forces which may lead to development of macular hole.

[Umbilical fibrous hamartoma of infancy: A case report]. / Hamartoma fibroso de la infancia umbilical: Reporte de un caso.

INTRODUCTION: Fibrous hamartoma of infancy (FHI) is a benign, soft tissue tumor that usually oc curs in children and has a characteristic histological morphology. OBJECTIVE: To describe a case of congenital FHI with atypical histological and clinical characteristics. CLINICAL CASE: Full-term male newborn, with no perinatal morbid history was referred to dermatology due to a congenital erythe matous plaque in the umbilical region. The histological study showed a fusocelullar proliferation in dermis and hypodermis of biphasic distribution, with an infiltrative, swirling pattern and bundles of spindle fibroblast-like and myofibroblast-like cells, associated in depth with a mature adipose tissue component. The immunohistochemical study revealed diffuse positivity for CD34, and focal posi tivity for FXIIIa, without immunoreactivity for actin, desmin, MyoD1, S100, HMB45, Melan-A, or EMA. Fluorescent in situ hybridization (FISH) was negative for platelet-derived growth factor recep tor beta (PDGFR-beta) and for ETV6 gene. PDGFR-beta and ETV6 gene are present in congenital dermatofibrosarcoma protuberans and infantile fibrosarcoma, respectively. This history, in addition to previous histological findings, supported the diagnosis of FHI. Surgical resection was performed, without signs of recurrence during clinical follow-up. CONCLUSION: It is important to consider the FHI within the differential diagnosis of subcutaneous tumors in children, especially in those under two years of age. Although its behavior is benign, it is similar to multiple benign and malignant le sions, which makes it imperative to perform a histological study in front of suspicious clinical lesions.

Congenital neurocristic cutaneous hamartoma with poliosis: A case report.

Neurocristic cutaneous hamartomas (NCH) are rare, pigmented skin lesions derived from the abnormal migration of neural crest cells. We report the case of a 57-year-old female with a congenital localized area of poliosis and underlying pigmented patch on her scalp. Analysis of 2 punch biopsies yielded features consistent with NCH. Histopathology revealed schwannian-differentiated spindle cells and melanocytic components in the dermis. The spindle cells stained positively for S-100 and the stroma showed a prominent CD34 staining. The melanocytes were positive for melanoma triple stain (HMB-45, Melan A, Tyrosinase) and S-100. As the presentation of NCH and focal poliosis has yet to be described, we will present a literature review of NCH and discuss common features and associations of poliosis.