'Monster cell' melanoma with pulmonary metastasis and cyclin D1 amplification.

Markedly pleomorphic epithelioid cells with high mitotic activity, giant cell formation, very large atypical nuclei, multiple nucleoli and abundant cytoplasm characterize 'monster' cells and may indicate aggressive tumor behavior. Very rare reports of melanomas comprised of 'monster cells' or cells with comparable histomorphological features, found in tissue samples from skin, lymph nodes, CNS, oral cavity and ileum have been published in the literature. This case is the first such description in the lung, and it is characterized with a battery of immunohistochemical stains; BRAF mutation status was negative, and fluorescence in situ hybridization analysis revealed increased copy number gains in 11q (cyclin D1), which is associated with poor prognosis in melanoma. The presence of monster cells in melanoma was associated with aggressive behavior in the reported patient.

Combined melanocytic nevi: histologic variants and melanoma mimics.

Combined melanocytic nevi are composed of 2 or more distinct populations of nevomelanocytes. Most commonly used to describe the combination of blue nevi with common nevi, it may also be applied to other combinations of benign melanocytic proliferations, including Spitz nevi and nevi with deep dermal pigmented nevomelanocytes. We report the incidence and distribution of these tumors at the Massachusetts General Hospital over the past decade and review guidelines for diagnostic criteria and nomenclature. Between 2000 and 2010 we identified 511 cases of combined nevi, represented by 4 histologically distinct diagnostic categories: (1) blue nevus, (2) nevi with deep dermal pigmented nevomelanocytes (plexiform/deep penetrating, inverted type A/clonal), (3) Spitz or pigmented spindled cell nevus, combined with another type of nevus (usually common or dysplastic), and (4) other combinations including 2 or more nevus types. Nearly one fifth of these tumors displayed atypical features; atypia was observed more often in combined nevi with Spitz or deep pigmented elements (26 of 55, 47%, and 25 of 98, 26%, respectively) than in combined common and blue nevi (37 of 336, 11%). Clinical follow-up data were available for 83% of the patients with atypical combined nevi; none developed recurrence or metastasis with a mean follow-up of over 4 years.

Patient with amyloidoma of the ulnar nerve and salivary glands.

Amyloidomas of the peripheral nervous system have been reported rarely. We describe a patient with a history of localized amyloidosis of the salivary glands who presented a few years later with paresthesias of her left medial arm, forearm, and fifth digit. A mass affecting the left ulnar nerve was confirmed by MRI studies. It was excised and proven on pathological examination to be an amyloidoma. The benign course of this patient's illness is consistent with localized amyloidosis affecting two different organs.

Apocrine mixed tumor of the skin with a prominent pilomatricomal component.

Pilomatrical differentiation within an apocrine mixed tumor (AMT) when present is only focal and has not been reported to be extensive. We herein report an AMT with prominent pilomatrical differentiation. A 47-year-old male presented with a 0.7 cm lesion on the right eyebrow. Histologic sections revealed, underneath a neurofibroma, a well-circumscribed tumor composed of nodules of branching epithelial elements and occasional keratinous cysts within a myxoid and lipomatous stroma. The ductal structures appeared to be composed of two layers of basophilic cuboidal cells and exhibited decapitation secretion. In approximately 50% of the tumor, eosinophilic ghost/shadow cells associated with a foreign body giant cell reaction formed a nodule resembling a pilomatricoma. Focally, columns of matrical cells were seen giving rise to shadow cells. Cytokeratin (CK) 5/6 and CK14 labeled the epithelial component. CK7, CK19 and Ber-EP4 labeled the ductal structures. Carcinoembryonic antigen and epithelial membrane antigen highlighted the luminal surface. S100 stained the stromal cells within the myxoid matrix, adipocytes and spindle cells within the overlying neurofibroma. CK10 highlighted the corneocytes within the keratinous cysts. CK17 labeled the epithelial lining of the keratinous cyst. The presence of follicular and apocrine differentiation within our tumor reinforces the common embryologic derivation of these elements.

Atypical thymoma: a report of seven patients.

BACKGROUND: Most thymic neoplasms fall under the designation of thymoma, consisting of well-differentiated epithelial cells, resembling normal thymus. At the opposite spectrum are thymic carcinomas; the cell of origin while similar is malignant. Recently a third category of thymic neoplasms, atypical thymomas, has been recognized representing thymic neoplasms manifesting atypia although without overt cytomorphologic criteria of malignancy. METHODS: Seven patients with a diagnosis of atypical thymoma were encountered over a 6-year period from the patient files of the cardiothoracic division of The Ohio State Medical Center. RESULTS: In all patients there was gross or light microscopic invasive disease with involvement of the capsule, phrenic nerve, diaphragm, chest wall, and lung. Surgical extirpation/de-bulking along with radiation therapy in six and chemotherapy in one led to complete disease regression. Intrathoracic recurrences developed in 4 involving lung, pleura, chest wall and diaphragm. All patients are well. CONCLUSIONS: Atypical thymomas are locally aggressive tumors with a high incidence of intrathoracic recurrence; extrathoracic spread is not seen. Our study corroborates other reports that death attributable to atypical thymoma is uncommon.