Neurocristic Hamartoma Research Articles

Case of a Newborn with a Neurocristic Hamartoma in a Congenital Melanocytic Naevi.

We present the case of a newborn female that was referred for review of a large melanocytic lesion on the lower back and multiple smaller lesions. Two biopsies were taken which showed features of congenital naevus and a small component of spindled dendritic cells that showed no positivity with melanocytic markers. As such, the histopathological findings of these biopsies were consistent with a diagnosis of a congenital naevus with areas resembling a neurocristic hamartoma. This case serves to highlight this rare condition and its clinical presentation, histopathological features and the importance of its early diagnosis and surveillance.

Dermoscopy of Cutaneous Neurocristic Hamartoma and Report of its Rare Clinical Presentation.

Dermoscopy of Cutaneous Neurocristic Hamartoma and Report of its Rare Clinical Presentation.

Melanotic Neurofibroma: A Case Report

Introduction: Melanotic neurofibromas are rare tumours, derived from peripheral nerve sheath, whose originality consists in the presence of melanic pigment. The clinical and histological diagnosis is often difficult to make requiring the immunohistochemical exam to make the difference between melanotic neurofibroma and the other pigmented tumors. Melanotic neurofibroma has a good prognosis and the malignization is rare. Case Report: A 22 year-old man presented since childhood a left occipital tumor, it had a firm consistency and pigmented color. CT objectified isodense occipital mass, which enhanced heterogeneously after contrast product. Lack of bone loss beside. Complete surgical excision was performed. Histological and immunohistochemical analysis led to the diagnosis of melanotic neurofibroma. Discussion: Pigmented neurofibroma is a rare variant of neurofibroma showing melanin production and constitute less than 1% of all cases. It can occur on their own or be associated with neurofibromatosis. They must be distinguished from classical neurofibromas when pigmentation occurs in the latter. Melanotic neurofibromas usually appear in the second or third decade of life and rarely in childhood. The clinical diagnosis is difficult to establish requiring the histopathological examination to differentiate between the melanotic neurofibroma and other pigmented tumours. It can mimicking a giant naevus or a neurocristic cutaneous hamartoma. These are the two main differential diagnoses among children. Among adults, the main difficulty is to distinguish melanotic neurofibroma from pigmented dermatofibrosarcoma. The elective treatment is surgical, represented by the complete excision of the tumor. Conclusion: Pigmented neurofibroma is a unique subtype of neurofibroma which is rare and contains melanin producing cells. The histopathological features with unique pattern of melanogenesis, ultrastructural findings and immunohistochemistry will enable us to diagnose this entity and differentiate it from other pigmented tumours of skin.

Cutaneous neurocristic hamartoma on the scalp

Cutaneous neurocristic hamartoma on the scalp

Cutaneous Neurocristic Hamartoma Presenting as Cutis Verticis Gyrata

Cutaneous neurocristic hamartoma is a rare developmental complex melanocytic lesion of neural crest origin in the dermis and subcutis with diverse histological differentiation including melanocytic, neurosustentacular, and mesenchymal elements. Cutis verticis gyrata is a cerebriform thickening of the scalp manifesting as folds, ridges, or creases. We report a case of cutaneous neurocristic hamartoma of the scalp in a 20-year-old woman presenting as cutis verticis gyrata. Microscopically, the lesion involved the dermis and the subcutis. Dendritic pigmented melanocytes were seen in between the collagen bands. Plexiform islands consisting of cords and palisades of spindled cells were also apparent. Immunohistochemically, HMB-45 positivity was observed in the dendritic melanocytic cells. S-100 protein was positive in dendritic melanocytes and in the Schwannian cells. The stromal cells showed CD34 staining. This lesion is presented because of its rarity, unusual clinical appearance, and resemblance to both a neurocristic hamartoma and large plaque type of blue nevus.

Congenital Combined Melanocytic Nevus of the Scalp With Associated Alopecia Areata

We report a case of a 20-year-old Chinese man with an alopecic congenital combined compound and blue melanocytic nevus of the scalp, associated with alopecia areata. The diagnosis of a combined melanocytic nevus was confirmed by histopathological examination and immunohistochemical stains, with exclusion of neurocristic hamartoma, which can have a similar clinical and histopathological appearance but different prognosis. In addition, we explore the association of this large melanocytic lesion with alopecia areata.

Congenital Myxoid and Pigmented Dermatofibrosarcoma Protuberans: A Case Report

Dermatofibrosarcoma protuberans (DFSP) is a low-grade, mesenchymal, spindle cell tumor. In addition to the classical form characterized by a storiform pattern of tumor cells, pigmented (Bednar's tumor) and myxoid variants can be observed. Classical DFSP and Bednar's tumor are easily diagnosed. The myxoid variant represents a diagnostic challenge. Pigmented and myxoid variants are rare and thus far have never been reported in association in congenital DFSP. We came across a unique DFSP that was, at the same time, congenital, pigmented, and myxoid. The tumor was surgically excised with broad free margins and no recurrence. The differential diagnosis with other entities such as giant cell fibroblastoma, CD34-positive plaque-like dermal fibroma, superficial plaque-like CD34 DFSP, and neurocristic hamartoma is discussed. The recognition of this hybrid variant of congenital DFSP is important to avoid under- or overtreatment.

Malignant Neurocristic Hamartoma: A Pitfall for Melanoma and Malignant Blue Nevus

Neurocristic hamartomas (NCHs), proliferations of melanocytes; Schwann cells; and pigmented, spindled, and dendritic blue nevus cells, are very rarely

Extensive Neurocristic Hamartoma With Bone Marrow Involvement

Cutaneous neurocristic hamartoma (NCH) is a rare, pigmented lesion consisting of cells that aberrantly develop from the neurocrest. In addition to a dermal melanocytic component, NCH can also harbor neurosustentacular and neuromesenchymal components. NCH has many features in common with other dermal melanocytic neoplasm, such as blue nevi. Recognition of NCH is important not only because of the potential for misinterpretation as melanoma, but also because melanoma arise within these lesions over an unpredictable time frame and remain undetected because of the deep location and already pigmented background. We report a case of a 17-year-old man with a large NCH resected from the posterior scalp showing involvement of the bone marrow.

Blue Nevi and Related Lesions

Blue nevi and related entities are a heterogenous group of congenital and acquired melanocytic tumors that includes established entities such as dendritic ("common") blue nevus and cellular blue nevus, and their numerous clinical and pathologic variants, such as deep penetrating nevus. They share several clinical and morphologic features including their blue tinctorial properties, the presence of a dermal proliferation of spindle, fusiform or ovoid cells, associated melanin pigment (both within the melanocytic tumor cells and also within macrophages) and stromal sclerosis and, at least focal positivity for HMB-45 (Gp100). Some variants, such as deep penetrating nevus, often show considerable variation in nuclear size and shape, and, as a consequence, are at risk of being misdiagnosed as melanoma by those unfamiliar with their characteristic morphologic features. The so-called malignant blue nevus is a controversial term denoting melanomas arising in association with or exhibiting some morphologic similarities to blue nevus. There are also lesions that are probably related to blue nevi, such as the recently described pigmented epithelioid melanocytoma and the neurocristic hamartomas, whose nature, biologic behavior, and relationship to the better established entities remains to be clearly established. This review aims to present a brief overview of these lesions, highlighting their pathologic characteristics, distinguishing features and potential diagnostic pitfalls, with particular emphasis on recently described entities, molecular findings, controversial areas, and approaches to diagnosis.

Large plaque-type blue naevus with subcutaneous cellular nodules

We report a new case of 'large plaque-type blue naevus (PTBN) with subcutaneous cellular nodules' involving the breast. A 25-year-old-woman presented with a large plaque, 140 x 100 mm in size, on the right chest wall involving the right breast, associated with recent subcutaneous nodules. Histopathological examination revealed features of cellular and common blue naevus. Dermatoscopy was performed, and the diagnosis of PTBN was made. PTBN is a rare condition with an imprecise prognosis. In cases of PBTN lesions on the head, clinicians must keep in mind the risk of malignant transformation of PTBN or an association with cutaneous neurocristic hamartoma. For this new variant of PTBN appearing on the trunk, we propose close monitoring of the patient if surgical excision is impossible.

Extensive neurocristic hamartoma with skeletal muscle involvement

Neurocristic hamartomas (NCH) are rare pigmented skin lesions based in the deep subcutaneous tissues that may be either congenital or acquired. The clinical importance of these lesions is the potential for misdiagnosis and the development of malignant melanomas over a poorly described time course. Histological pleomorphism precludes meaningful random biopsies as a means of cancer surveillance. We present the case of an extensive NCH in a 67-year-old man, with a reported duration of greater than 50 years and no current clinical or histological indication of malignancy. Incisional biopsies of nodular areas showed bland-appearing pigmented cells that extended into subcutaneous adipose tissue and skeletal muscle. The specimens contained numerous clusters of differing configurations and cell types. Positron emission tomography (PET) scanning was used as an adjunct to physical examination in follow up. A PET-avid mass was detected but proved to be a banal nodular melanocytic proliferation within the NCH. In conclusion, NCH may be characterized by extensive deep tissue involvement in the absence of overt malignancy. The possible development of malignant melanoma in such lesions warrants close surveillance.

Cutaneous neurocristic hamartoma with blue naevus‐like features and plexiform dermal hyperneury

Cutaneous neurocristic hamartoma with blue naevus‐like features and plexiform dermal hyperneury

Oral 1 Congenital neurocristic hamartoma presenting as tumour within the central nervous system

Oral 1 Congenital neurocristic hamartoma presenting as tumour within the central nervous system

Dermal melanocytic proliferation with features of a plaque-type blue nevus and neurocristic hamartoma

Blue nevi (BN) and neurocristic hamartomas (NCH) are pigmented lesions that originate from the aberrant development of cells derived from the neural crest. BN are composed of dermal melanocytes, whereas NCH have a broader histology and show Schwann cell differentiation as well. In addition, BN and NCH might differ in their potential to develop into a malignancy. We describe a patient with a lesion showing features of both a plaque-type BN and NCH.

Genetic Changes in Neoplasms Arising in Congenital Melanocytic Nevi: Differences Between Nodular Proliferations and Melanomas

Large congenital melanocytic nevi (CMN) are at an increased risk of developing melanoma. Several forms of secondary proliferations can arise in congenital nevi on rare occasions. Although some of these closely resemble melanoma both clinically and histologically, metastasis is rare. We used comparative genomic hybridization to analyze chromosomal aberrations in different types of proliferations arising in CMN and compared them to typical congenital nevi, clear-cut melanomas arising in congenital nevi, as well as primary cutaneous melanomas that were not associated with a CMN. Cases of CMN and CMN with secondary proliferations were assigned to six groups according to the predominant histological pattern: group I, bland congenital nevi (n = 6); group II, congenital nevi with foci of increased cellularity (n = 4); group III, CMN with a proliferation simulating superficial spreading melanoma in situ (n = 3); group IV, CMN with a proliferation simulating nodular melanoma (n = 9); group V, proliferating neurocristic hamartoma (n = 1); and group VI, melanoma arising in congenital nevus (n = 6). No aberrations were found in groups I to III, whereas seven of nine cases of group IV, and one of one case of group V, showed aberrations. In group IV six of seven cases with aberrations (86%) showed numerical aberrations of whole chromosomes exclusively. This pattern differed significantly from the findings in melanoma that arose within CMN (n = 6), group VI, or independent of CMN (n = 122) in which only 5% showed numerical changes only. The single case in group V showed aberrations similar to melanoma. The finding of frequent numerical chromosomal aberrations in atypical nodular proliferations arising in CMN identifies these as clonal neoplasms with a genomic instability consistent with a mitotic spindle checkpoint defect. This difference compared to the aberration pattern found in melanoma might explain their more benign clinical behavior and may be of diagnostic value in ambiguous cases.

The Relationship Between Melanocytes and Peripheral Nerve Sheath Cells (Part II): Blue Nevus With Peripheral Nerve Sheath Differentiation

Peripheral nerve sheath differentiation was studied in 120 specimens of blue nevi (112 specimens of "common" blue nevi and 8 specimens of "cellular" blue nevi). In 10 of 112 common blue nevi, fascicles of pigmented dendritic melanocytes or less pigmented spindle-shaped melanocytes with S-shaped nuclei were associated with wavy delicate collagen bundles. In 4 of these 10 specimens, the melanocytes showed a perifollicular arrangement. These nerve fascicle-like structures were seen in some cellular blue nevi (5 of 8 specimens). Structures closely resembling authentic nerve fascicles were not observed in common or cellular blue nevi. The fascicles with S-shaped nuclei and fibrillary collagenous tissue observed in blue nevi (which were well detected in the cellular type but rarely found in the common type) may be peripheral nerve sheath features and perhaps evidence that dermal dendritic melanocytes in the reticular dermis may have arisen within a peripheral nerve sheath milieu from primitive fibroblast-like precursors. Some of the examples presented here may be identical to those reported for "pilar neurocristic hamartoma" or "neurocristic hamartoma." I also speculate on the pathogenesis of blue nevi based on the observations made in this study.

TWO CASES OF NEVUS FUSCOCAERULEUS WITH PAIN, INCLUDING A CASE OF PILAR NEUROCRISTIC HAMARTOMA

ABSTRACTTwo patients with nevus fuscocaeruleus over the back and simultaneous pain were reported. Although the significance of this association remains to be clarified, it is interesting because the dermal melanocytes and nerves are of neuroectodermal origin. Histology of one case revealed findings consistent with those of pilar neurocristic hamartoma (1). Electron microscopy revealed dermal melanocytes in the neighborhood of a nerve. Photographic studies confirmed Morikawa's view (2) that the location of melanin may be examined by reflection ultraviolet photography, conventional photography, and infrared photography.

Pilar Neurocristic Hamartoma

A unique pigmented lesion, judged to be a hamartoma of neural crest origin, occurring in a female patient, is compared with equine melanotic disease, The characteristic perifollicular arrangement of pigment-laden spindle cells is remarkably similar in both. Previously described patch- and plaque-like blue nevi in humans are also closely related. Light and ultrastructural features showed differentiation toward both nevus cells and Schwann cells, and it is proposed that the lesion be termed pilar neurocristic hamartoma.