Presentation of a Smooth Muscle Hamartoma in the Bulbar Conjunctiva of an Adolescent Boy: A Case Report and Review of Literature.

PURPOSE: The aim of this study was to describe a novel presentation of conjunctival smooth muscle hamartoma and review the histopathologic findings of this entity. METHODS: A 17-year-old African American adolescent boy presented with a pink, nontender lesion of the right bulbar conjunctiva that did not improve with medical management. He had no previous medical or ocular history. The lesion was excised. RESULTS: Histopathologic examination disclosed morphologically benign smooth muscle bundles within the substantia propria that stained positively for smooth muscle actin, vimentin, and desmin consistent with the diagnosis of a smooth muscle hamartoma. CONCLUSIONS: Although congenital smooth muscle hamartomas of the conjunctiva have been rarely reported in the literature, this is the first described case of a smooth muscle hamartoma presenting in adolescence in the bulbar conjunctiva. This lesion should be considered in the differential diagnosis for adolescents with similar appearing lesions.

Simple Congenital Hamartoma of Retinal Pigment Epithelium.

A 45-year female presented in the Outpatient Department of a tertiary care hospital of Lahore with dimness of vision in the right eye. Her history revealed that the patient had noticed decreased vision since her childhood. Fundus examination revealed a jet-black slightly raised lesion about the size of »-disc diameter, located in the centre of macula. Optical coherence tomography (OCT) showed a highly hyper-reflective lesion at the fovea with sharp steep shadowing of the underlying structures due to backscattering. We excluded congenital hypertrophy of the retinal pigment epithelium (CHRPE) from our differential diagnosis, as solitary CHRPE is a flat well-demarcated lesion at the level of retinal pigment epithelium (RPE). Adenoma of RPE was eliminated as it has a large feeding and draining blood vessels with intra- and sub-retinal exudation. Choroid and surrounding retina was normal in our patient, which was helpful in differentiating it from choroidal nevus/choroidal melanoma. Our final diagnosis was simple congenital hamartoma of RPE. Key Words: Hamartoma, Retinal pigment epithelium, Macula.

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.

[Naevus unius lateris: a confusing entity (a case report)]. / Nævus unius lateris: un nævus déroutant (à propos d´un cas).

Naevus unius lateris is a rare congenital hamartoma, originating from the ectoderm. It is considered as a verruquous variant of the epidermal naevus. Given its extensive unilateral distribution, it is frequently associated with neurological, musculoskeletal, auditory and visual abnormalities. We here report the case of a 9-year-old child with nevus unius lateris associated with neurological and eye abnormalities.

THE "-OMAS" and "-OPIAS": Targeted and Philosophical Considerations Regarding Hamartomas, Choristomas, Teratomas, Ectopias, and Heterotopias in Pediatric Otorhinolaryngologic Pathology.

The spectrum of "developmental" lesions that occur in the head and neck predominantly congenital in origin and arising at birth and/or discovered in childhood is broad and fascinating. These have been grouped into categories such as "ectopias", "heterotopias", "hamartomas", and "choristomas". On a philosophical and consequently systematic level, these lesions, mostly benign tumors seem to lack a true understanding of the pathogenetic foundation on which to base a more unified taxonomic designation. In this review, we will consider some of these select tumors as they represent syndromic associations (nasal chondromesenchymal hamartoma and DICER1 syndrome), the lingual choristoma from the perspective of its nomenclature and classification, lesions with ectopic meningothelial elements, and teratomas and the enigmatic "hairy polyp" in reference to a broader discussion of pathogenesis and pluripotent cells in the head and neck. A consistent thread will be how these lesions are designated with some final thoughts on future directions regarding the investigation of their pathogenesis and taxonomic nomenclature.

Congenital Midline Spinal Hamartoma in a 5-Month-Old Infant.

BACKGROUND: Congenital midline spinal hamartoma is a very rare tumor-like proliferation that mostly occurs during childhood. It consists of mature, well-differentiated ectodermal and mesodermal elements that present in an abnormal location and are mostly associated with neurofibromatosis type 1 and spinal dysraphism. CASE DESCRIPTION: A 5-month-old male patient presented with complaint of a bump over the lower back. The bump was already present since birth with the size of approximately 3 cm in diameter and slow growth. There were no other associated symptoms besides the bump on the lower back. In the physical examination, we found a subcutaneous mass with associated skin dimple located on the midline of the lower back. Computed tomography scan of the spine showed a mass that arose from inside the dura and a closed spinal dysraphism from L3 vertebra to the sacrum. A subtotal resection was performed, and the histopathology feature showed fat cells, cartilage, skeletal muscle fibers, nerve, and blood vessel. After 6 months follow-up, no symptoms or neurologic deficit were present, and no further growth was shown on the latest computed tomography scan. CONCLUSIONS: Congenital midline spinal hamartoma is very rare and seldom addressed. Most patients present with a cosmetic defect and rarely with associated symptoms. Tissue biopsy is still the best modality to definitively diagnose hamartoma and to exclude other diagnoses. Surgical excision of the tumor is still the mainstay treatment, especially for patients who are not neurologically intact and to correct the cosmetic skin defect.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IMAGING OF A CONGENITAL SIMPLE HAMARTOMA OF THE RETINAL PIGMENT EPITHELIUM.

PURPOSE: To report the case of a small pigmented tumor in the macular region investigated using optical coherence tomography angiography (OCT-A) in the context of a multimodal approach. METHODS: Case report. RESULTS: A 24-year-old man was referred for evaluation of an asymptomatic unilateral round comma-shaped pigmented tumor located in the macular region of his right eye. Spectral-domain OCT revealed an irregular hyperreflective mass within the retina, with a thickened hyaloid membrane and abrupt margins, and a complete posterior shadowing effect. On fluorescein angiography, early hyperfluorescence without leakage in the middle and late phases and a subtle halo of hyperfluorescence in the late phase were observed. OCT-A revealed the presence of intrinsic vascularization at the level of the inner capillary plexus, with signal intensity present at the level of the outer capillary plexus. In the superficial scans, the retinal vessels were oriented radially to the lesion and were in continuity with the vascular network within the tumor mass. No choroidal vessels could be identified. CONCLUSION: We report the case of a congenital simple hamartoma of the retinal pigment epithelium investigated using OCT-A as part of multimodal imaging. OCT-A provided a new insight in the assessment of the lesion, differential diagnosis, and follow-up of the patient. This imaging modality could be an important non-invasive tool in the management of congenital hamartomas of the retinal pigment epithelium.

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.

Foveal Congenital Simple Hamartoma of Retinal Pigment Epithelium: A Report of Two Cases.

We report two cases with foveal congenital simple hamartoma of the retinal pigment epithelium (CSHRPE), as both patients presented to our retina services complaining of a unilateral decreased vision. Full ophthalmic examination and multimodal imaging were performed including fundus photography, fundus autofluorescence, optical coherence tomography, fluorescein angiography, and electrophysiological testing. Both patients presented with 20/80 vision in the affected eyes. Foveal CSHRPE was found in both eyes, along with parapapillary hyperpigmented rim, multiple pinpoint macular lesions, and few posterior pole hyperpigmented lesions. Multifocal electroretinogram showed diminished central amplitude in both eyes, with three-dimensional topography map showing blunted foveal peaks in one eye and the absence of a central peak in the other patient. Both patients had a stable vision and clinical examination of the CSHRPE during 5 and 6 years follow up, respectively. Foveal CSHRPE is usually symptomatic and results in a decline in visual acuity. Follow-up of these patients showed stable vision and clinical examination.

Nasal Chondromesenchymal Hamartoma.

Nasal chondromesenchymal hamartoma (NCMH) is a rare, benign lesion of the sinonasal tract. It usually presents as a polypoid mass in infants and older children. Imaging studies and endoscopy are required to delineate the extent of the lesion and aid in its excision. This unusual lesion is composed of proliferating mesenchymal and cartilaginous elements. Recently, a genetic association between NCMH and DICER1 mutation has been established. It is important for pathologists to be familiar with this entity to avoid misdiagnosis since the lesion is benign and surgical excision is curative.

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.

Congenital Cystic Lesions of the Bile Ducts: Imaging-Based Diagnosis.

Congenital cystic lesions of the bile ducts represent a spectrum of liver and biliary system lesions, resulting from abnormal embryologic development of the ductal plate. These disorders include Caroli disease, choledochal cysts, autosomal dominant polycystic liver disease, congenital hepatic fibrosis, and biliary hamartomas. Each disorder carries a peculiar clinical presentation, prognosis, and risk of complications. Knowledge of radiological findings of fibropolycystic liver diseases is crucial for their appropriate detection and for differential diagnosis with other similar hepatic cystic lesions, in order to avoid relevant misdiagnosis. The aim of this review is to provide an illustrative summary of the most relevant imaging findings of these conditions as encountered on ultrasound, computed tomography, and magnetic resonance imaging, and provide pearls for imaging-based differential diagnosis.

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.