M87. Lumbar back. Irregular pigmented lesion. Melanocytic Club 213 Dr Richard Carr Warwick Hospital Slide Club Panel •Compound naevus with atypia •Benign compound naevus with area showing mildly atypical, active junctional nests and dermal sclerosis. No dermal mitotic activity or expansile nests. Radial margin 3mm. I favour a naevus with odd dermal sclerosis, but no convincing features for melanoma. •A compound nevus with congenital pattern features, and an adjacent region where there is fibroplasia with thickening of the papillary dermis, underlying mature nevus cells, and an overlying atypical junctional and superficial dermal proliferation. I believe these changes are consistent with a "fibrosing dysplastic nevus" as has been described in several series under various names. The asymmetrical character of the fibrosis is unusual. Diagnosis: Compound nevus with congenital pattern features, and adjacent fibrosing severely dysplastic changes, completely excised. Slide Club Panel •Compound naevus with some atypia. Considered dysplasia but may have been traumatised. No convincing evidence of melanoma. •Dysplastic naevus •Compound melanocytic nevus with one sclerotic area mimicking melanoma, probably due to associated lichen sclerosus et atrophicus or another sclerotic process involving superficial dermis. •Focal scarring in a compound naevus. Scar has created area of junctional atypia. Needs clinical correlation to determine whether the lesion has been traumatised. •Favour predominantly intradermal compound melanocytic naevus, peripheral region showing dysplastic changes involving the junctional zone. Some minor dermal scarring (? prior trauma or possibly superficial dermal regression) beneath the focus showing dysplastic changes (clinicopathological correlation). We cannot see convincing evidence for in situ malignancy and no evidence of dermal invasive malignancy is seen Slide Club Panel •I would favour a benign lesion. One shoulder with hyaline fibrosis in the dermis and a flattened epidermis with increased junctional activity with some atypia, but no ascending cells (recurrent nevus like). Previous treatment or traumatisation? DD regression seems less likely to me. In case of complete excision I would favour a wait and see policy, also taken into account the patients's age. •The lesion is unusual in 87 yrs-old. Melanocytes are irregular, but I could not see mitoses or necrotic melanocytes. For excluding nevoid melanoma I would apply IHC and particularly Ki67 •These lesions with nests of cells in regressed areas are often very difficult to classify in the absence of severe cytological atypia or dermal mitotic activity. Treat as for invasive melanoma Slide Club Panel • Atypical biphasic lesion: atypical intra-epidermal and dermal nevoid melanoctyic proliferation with papillary dermal hyalinization, biologically indeterminate, arising in a compound nevus. The lesion is clearly concerning for neoplastic progression to "nevoid" melanoma with regression and thickness of about 1 mm (no mitoses or ulceration). However, I consider the lesion indeterminate and to lack sufficient criteria for unequivocal melanoma. Would advise re-excision in order to achieve about 1 cm margins. Controversial lesion undoubtedly eliciting interpretations of benign, borderline, and malignant. • Superficial spreading melanoma, also compound naevus. • Junctional component looks atypical and this would be MIS, but the dark naevoid cells in dermis are not the same as other dermal cells and I would be suspicious that these were also malignant so would call this vertical GP. Slide Club Panel • The architecture is very asymmetrical with at one side a classic combined nevus with “congenital like architecture” and at the other side a disorganized mainly junctional proliferation of large epithelioid pigmented melanocytes. This cytology is rather typical of SSM, pagetoid spread is however not clearly present. Some extension to pilar sheath is seen at one side. The difficulty is the evaluation of the Breslow and Clark measures. There are some superficial dermal nests that harbor the same cytology as the malignant junctional nests. No mitotic figure was seen. Clinically the irregular pigmentation is explained by the lateral amount of melanophages surrounding those dermal nests. The whole melanocytic lesion (melanoma + nevus) does not exceed 1mm thickness but I cannot precisely measure the Breslow. It is usually recommended to analyze at least 6 sections to evaluate mitotic activity. I would recommend 1cm margins and surveillance. Case 214. M76. Right upper abdomen. Longstanding naeuvs, changed last 3/12. ?DN, ?MM Dr Richard A. Carr, Warwick Hospital Slide Club Panel • Compound dysplastic naevus with moderate cytological atypia and an area of superficial dermal fibrosis, but no other worrying features for an invasive-type melanoma. Radial margin 2mm. Had the lesion been traumatised? • Dysplastic naevus • “Dysplastic junctional melanocytic nevus with a focus of metaplastic ossification in the underlying dermis.” • “favour a superficially "irritated" pigmented predominantly junctional dysplastic naevus with patchy superficial dermal regression. We cannot see histological evidence for malignancy in the residual part of the lesion in the section sent for review. Slide Club Panel • SSM with partial regression. Clearly atypical melanocytes, lots of single cells that are ascending within the epidermis. Also in part atypical dermal component and clearly regression • Microinvasive melanoma to be treated as in situ melanoma. • Focal suprabasal spread just amounting to in situ melanoma, perhaps in an atypical naevus. Small possible dermal component, no mitoses in it, uncertain malignant potential - would do levels and treat as for pT1a melanoma • Severe junctional naevus v Melanoma in situ. Just enough atypia and confluence for MIS. Possible focal invasion but would like to see more sections • Melanoma, Clark III, 0,3mm with focal regression in toto excised; additional finding osteoma cutis in dermis. Slide Club Panel • “Borderline lesion with significant atypia. On balance severe dysplasia is favoured over melanoma.” • A superficial moderately to highly cellular proliferation of spindled to epithelioid melanocytes, about 3 mm in diameter on the slide. There is moderate nuclear variability with a few scattered larger nuclei. There are bridging nests. Differential diagnosis includes a severely dysplastic nevus versus a pigmented spindle cell nevus. There is moderate actinic elastosis, tending to favor the former diagnosis, although the small size tends to favor the latter. Diagnosis: Superficial atypical melanocytic proliferation of uncertain significance most consistent with a severely dysplastic nevus, completely excised. • Severely atypical compound melanocytic lesion bordering on early melanoma. Slide Club Panel • Atypical lentiginous compound melanocytic proliferation with evidence of partial regression. Small diameter (~4 mm); asymmetrical; contiguous atypical lentiginous melanocytic proliferation; limited pagetoid scatter; solar elastosis. I consider the lesion indeterminate but one can make the case for incipient melanoma in situ with partial regression because of contiguous atypical melanocytic proliferation, evolving in a lentiginous dysplastic nevus. Would advise final surgical margins of about 5 mm. Another undoubtedly controversial lesion with interpretations of benign (dysplastic nevus), borderline, and malignant. • Atypical junctional component is at least MIS - not sure if dermal component so would call radial GP. • very difficult case...overlapping elements... mainly junctional with at the center a nested architecture of mid-sized pigmented spindled melanocytes associated with epidermal papillary hyperplasia... as long standing pre-existing nevus. At each side there is a dermal fibrosis with inflammation and blood vessels ectatic and an interruption of the papillary epidermal architecture. junctional nests to left side above the fibrosis (when epidermis is up) are atypical both by their architecture (continuous junctional proliferation binding thecal and lentiginous patterns) and cytology (large epithelioid melanocytes). Underneath there are several calcinosis indicative of prior folliculitis in the nevus. In our experience folliculitis can induced shortly after their resolution fibro-inflammatory reactions in the upper dermis of nevi (especially congenital nevi who have larger hair shafts that are more prone to folliculitis). In that setting some degree of atypia is induced in the surrounding melanocytes (both junctional and dermal). The calcinosis indicates however that these folliculitis took place a while ago. On the section with the less visible lesion there are images of pagetoid spreading along with with a dermal lymphocytic inflammatory reaction. The melanocytes are however not clearly atypical. The clinical presentation is globally worrisome and I suspect a lateral transformation of a pre-existing nevi. There are no dermal nests by fibrous modification that could be regressive. This regression would hamper both Breslow and clark evaluation. I would recommend 1cm margins and surveillance as for an early invasive melanoma. A clinical picture would maybe help me in this case. Piepkorn MW, Barnhill RL, Elder DE, Knezevich SR, Carney PA, Reisch LM, Elmore JG. The MPATH-Dx reporting schema for melanocytic proliferations and melanoma. J Am Acad Dermatol. 2014 Jan;70(1):131-41. MPATH-Dx is a research and potentially diagnostic reporting tool “greater agreement