Melanotic medullary thyroid carcinoma: A case report with review of the literature

Melanotic medullary thyroid carcinoma is morphologically defined by the presence of melanin deposits in the cytoplasm of tumor cells. It is an extremely rare variant with only 15 cases described in the literature to date and only one report of diagnosis by fine needle aspiration (FNA) biopsy. A 51-year-old woman presented with neck swelling. An ultrasound examination revealed a single solid nodule in the right thyroid lobe that measured 5.4 × 4.7 × 4.3 cm. Laboratory examination revealed elevated levels of serum calcitonin (8643.0 pg/ml), carcinoembryonic antigen (CEA) (86.2 ng/ml), and chromogranin A (123.2 ng/ml). An FNA biopsy of the thyroid nodule revealed predominantly single plasmacytoid cells with round to oval eccentric nuclei and dark brown intracytoplasmic granules. Immunohistochemical studies with Melan-A performed on a cell block slide confirmed that the granules contained melanin. The tumor cells were also positive for calcitonin, CEA, synaptophysin, AE1/AE3, CAM5.2, and HMB-45(focal); the tumor cells were negative for chromogranin, thyroglobulin, PAX8 and TTF-1. The diagnosis was reported as melanotic variant of medullary thyroid carcinoma. The patient underwent a total thyroidectomy which revealed tumor cell expression of insulinoma-associated protein 1 and confirmed neuroendocrine differentiation. Shortly after she presented with tumor recurrence in the thyroidectomy bed. The tumor cells were positive for only S100, SOX10, and Melan-A. Molecular analysis with the SEMA4 Solid Tumor Panel revealed mutations in the HRAS, PIK3CA, PIK3R1, MYC, and CCND3 genes. The final diagnosis was reported as melanocytic medullary thyroid carcinoma with high grade transformation and loss of epithelial and neuroendocrine expression.

Cis-acting mutation affecting GJA5 transcription is underlying the Melanotic within-feather pigmentation pattern in chickens

Melanotic (Ml) is a mutation in chickens that extends black (eumelanin) pigmentation in normally brown or red (pheomelanin) areas, thus affecting multiple within-feather patterns [J. W. Moore, J. R. Smyth Jr, J. Hered. 62, 215-219 (1971)]. In the present study, linkage mapping using a back-cross between Dark Cornish (Ml/Ml) and Partridge Plymouth Rock (ml+/ml+ ) chickens assigned Ml to an 820-kb region on chromosome 1. Identity-by-descent mapping, via whole-genome sequencing and diagnostic tests using a diverse set of chickens, refined the localization to the genomic region harboring GJA5 encoding gap-junction protein 5 (alias connexin 40) previously associated with pigmentation patterns in zebrafish. An insertion/deletion polymorphism located in the vicinity of the GJA5 promoter region was identified as the candidate causal mutation. Four different GJA5 transcripts were found to be expressed in feather follicles and at least two showed differential expression between genotypes. The results showed that Melanotic constitutes a cis-acting regulatory mutation affecting GJA5 expression. A recent study established the melanocortin-1 receptor (MC1R) locus and the interaction between the MC1R receptor and its antagonist agouti-signaling protein as the primary mechanism underlying variation in within-feather pigmentation patterns in chickens. The present study advances understanding the mechanisms underlying variation in plumage color in birds because it demonstrates that the activity of connexin 40/GJA5 can modulate the periodic pigmentation patterns within individual feathers.

L3 rootlet recurrent melanocytic schwannoma - case report and literature review

First described by Miller in 1932, melanocytic schwannoma (MS) (melanotic schwannoma, pigmented schwannoma) is a rare variation of peripheral nerve sheet tumours with ectodermal origin occurring predominantly in somatic, but also in the autonomic peripheral system with around two hundred cases in the literature. Predominantly benign tumours, MS are still imaging and pathological challenge and can be easily misdiagnosed with more aggressive peripheral nerve tumours.We report a case of melanocytic schwannoma on L3 sensory rootlet with systematic literature review of nearly 200 cases presented in intracranial, paraspinal region, thoracic, abdominal or pelvic cavities and skin. Two-thirds of cases are part of Carney complex.We present a case of a 61-year-old male with a 3-month history of low back pain, progressive numbness and stiffness in the right thigh, shin and knee, tibial and peroneal paresis causing gait disturbance and neurological claudication. MRI findings present "sand clock" type intradural extramedullary tumour formation with extension to the L3 rootlet through right L3-L4 foramen, hypointense on T2 and hyperintense on T1. Pathological diagnosis of sporadic type melanocytic schwannoma was made via immunohistological and ultrastructural analysis. Thirteen months after total resection there was clinical and MRI evidence of recurrence of the tumour. Total resection and radiosurgery was performed with a recurrence free period of 14 months.A gold standard for melanocytic schwannoma treatment is gross total surgical resection. Despite being considered benign tumours, MS have a local or metastatic recurrence of around 13%. MRI imaging in most of the cases is insufficient and only exhaustive pathological and immunohistological examination is the key to diagnosis. Need of postoperative radiation therapy is still controversial. For the first time, a criterion for postoperative adjuvant therapy was established.

Melanotic intracranial epidermoid: Case report and description of a new subtype

Intracranial epidermoids are generally seen as hypodense nonenhancing lesions on computed tomography scans; and, as T1 hypointense and T2 hyperintense lesions on magnetic resonance imaging (MRI). Unusual radiological findings have been reported earlier. The authors present the case of a 54-year old male patient who had prior intracranial surgery. On MRI, there was a thick peripheral mantle of diffusion restriction with a central core of brilliant T1 hyperintensity and very black T2 hypointensity. The peripheral mantle showing diffusion restriction was heterogeneously T1 hypointense and T2 hyperintense. At surgery, there was a typical pearly white epidermoid peripherally with a greenish-brown centre. Pathology showed abundant extracellular melanin which was also found in the basal layer. The authors present the first case of a melanin pigmented intracranial epidermoid in literature, describing a new histological subtype.

Primary malignant melanoma of the breast: case report and review of the literature

BACKGROUND

Melanoma of the breast is a rare disease and may present as a metastatic manifestation of primary cutaneous melanoma or as primary malignant melanoma of the breast (PMMB). Clinical presentations of PMMB vary and surgery is the mainstay of treatment.

CASE REPORT

We present the case of a 54-year-old woman with a primary malignant melanoma of the left breast. She was treated with mastectomy, axillary sentinel lymph node excision and primary reconstruction with a tissue expander. Final histology revealed a malignant melanoma with 10 cm in the largest diameter. Molecular characterization by DNA-sequencing showed B-RAF, N-RAS and c-kit wild types. Immunohistochemical characterization demonstrated weak expression of S100 and melan-A and strong expression of polyclonal S100. HMB45, tyrosine kinase and the cytokeratins AE1/AE3 and MNF 116 were not expressed. Lymphoma-specific markers (CD30, CD3, CD20) and sarcoma-specific markers (desmin, actin, CD34) were also negative. The tumor proliferation rate according to Mib1-staining was 90%. Staging of the abdomen, chest, head and bones showed no evidence of metastases. A dermatological examination showed no primary melanoma of the skin. Interferon-alpha was suggested as adjuvant therapy but declined by the patient. With a follow-up of 6 months, the patient is still alive with no evidence of disease.

CONCLUSION

PMMB is rare and may be successfully treated with surgical excision. Locally advanced PMMB may occur without regional and distant metastases.

Melanotic cyst of L5 spinal root: A case report and review of literature

Till date, 85 cases of melanotic schwannoma and 11 cases of spinal root melanoma have been reported in literature. We are reporting a case of a 45-year-old lady who presented with primary low back pain, and magnetic resonance imaging of lumbo-sacral spine showed at left L5-S1 foraminal lesion extending to the para-spinal compartment. Hemi-laminectomy, facetectomy, and excision of the lesion were done. It was primarily a cystic lesion with attachment to the exiting spinal nerve root. Histopathology of the cyst wall showed a fibro-collagenous stroma with no specific cell lining containing melanin pigment suggestive of a melanotic cyst. The patient was completely relieved of the back pain, and had no recurrence over a follow-up period of one and half years. This case is probably the first reported predominantly cystic, pigmented lesion, affecting the spinal root.