Unknown: A woman with nodular lesion in a patient with diabetes mellitus
J Aneiros-Fernandez MD1, S Arias-Santiago MD2, H Husein-Elahmed MD2, MA Fernandez-Pugnaire MD2, F O'Valle MD1
Dermatology Online Journal 17 (4): 8

1. Department of Pathology
2. Department of Dermatology
University Hospital, Granada, Spain



Answer: Clear cell eccrine porocarcinoma with squamous differentiation associated with diabetes mellitus


Figure 1 Figure 2
Figure 1. An exophytic ulcerated lesion

Figure 2. Histologic sections show of panoramic lesion

A 68-year-old woman was sent to the department of Dermatology because of a cutaneous nodule located on the front of the right leg that had grown progressively for the past six years. Clinical examination showed a nodule of firm consistency measuring 5 x 4 cm, with a crusted and eroded surface (Figure 1). The rest of her cutaneous exam was normal. The patient had a history of diabetes mellitus. There was no family history of similar lesions. Histologic sections are show in Figures 2, 3, and 4.


Figure 3 Figure 4
Figure 3. Histologic sections present two different patterns

Figure 4. Immunohistochemical staining (A) CEA and (B) EMA

Microscopic findings and clinical course

The histological study shows a neoplasm that is connected to the epidermis and is infiltrating into the dermis. The tumor consists of solid areas and areas with clear cells containing glycogen (PAS positive) (Figure 2). These cells show significant atypia. In another area of the tumor were identified areas of squamous differentiation (Figure 3 A and B).

Immunohistochemical study showed positivity in solid areas and staining for CEA, EMA (Figure 4 A and B). Areas of squamous differentiation were positive for cytokeratin and negative for EMA and CEA. Ki 67 staining showed high proliferative activity with 60 percent positive cells.

The tumor was treated with local excision with a margin of 1 cm without evidence of recurrence at 1 year and 6 months.


Discussion

Eccrine porocarcinoma is a rare cutaneous neoplasm that develops from the intraepithelial ductal portion of the eccrine sweat gland. The tumor generally grows slowly over a long period of time but may exhibit an accelerated growth phase. The eccrine porocarcinoma represents 0.01 percent of skin tumors. The etiology is unknown, although cases have been reported related to radiotherapy, trauma, and immunosuppression [1].

The tumor mainly affects women aged between 50 and 80 years [2]. The preferred location of these tumors is not related to skin areas with a higher number of eccrine glands. The most common locations are the extremities, head, and neck [2]. The size varies between 1 and 10 cm. The clinical findings of malignant transformation of poroma to porocarcinoma are rapid increases in size, bleeding, and ulceration of the epidermis.

The histological findings show several main features. The architectural pattern is defined by disorderly, irregular infiltration and the histologic features include nuclear atypia and mitosis. There are studies that discuss the presence of ductal differentiation, but there is no conclusive evidence that ductal differentiation is associated with the degree of malignancy, although it is helpful for diagnosis of tumors of eccrine origin [3].

There are different types of porocarcinoma depending on prominent cellular characteristics that include epithelioid cells, squamous cells, spindle cells, clear cells, and mucin-producing cells.

A rare finding in our case is the presence of the squamous cell-type of porocarcinoma because the acrosyringium luminal cells are of squamous type. Porocarcinoma with squamous differentiation is found more frequently in the lower extremities, although it has also been reported on the trunk, head, neck, upper limbs, vulva, breast, and nail bed [4]. Eccrine porocarcinoma with squamous differentiation has shown a better prognosis than squamous cell carcinoma [5].

Another rare finding in our case is the association of clear cell porocarcinoma with diabetes. The clear cells could represent the accumulation of glycogen in the cytoplasm of cells, because of a deficiency of phosphorylase caused by high concentrations of glucose in liver cells [6].

Eccrine porocarcinoma may exhibit local recurrences and nodal metastases, though less frequently. When lymph node metastases occur, the survival varies between 35 percent and 72 percent [7]. The treatment of choice is conservative excision with wide margins to prevent local recurrence.

References

1. Goedde TA, Bumpers H, Fiscella J, Rao U, Karakousis CP. Eccrine porocarcinoma. J Surg Oncol. 1994;55(4):261-4. [PubMed]

2. Robson A, Greene J, Ansari N, Kim B, Seed PT, McKee PH, Calonje E. Eccrine porocarcinoma (malignant eccrine poroma): a clinicopathologic study of 69 cases. Am J Surg Pathol. 2001;25(6):710-20. [PubMed]

3. Barzi AS, Ruggeri S, Recchia F, Bertoldi I. Malignant metastatic eccrine poroma. Proposal for a new therapeutic protocol. Dermatol Surg. 1997;23(4):267-72. PubMed [PubMed]

4. Mahomed F, Blok J, Grayson W. The squamous variant of eccrine porocarcinoma: a clinicopathological study of 21 cases. J Clin Pathol. 2008;61(3):361-5. [PubMed]

5. Herrero J, Monteagudo C, Jordá E, Llombart-Bosch A. Squamoid eccrine ductal carcinoma. Histopathology. 1998;32(5):478-80. [PubMed]

6. Requena L, Sarasa JL, Piqué E, Fariña MC, Olivares M, Martín L. Clear-cell porocarcinoma: another cutaneous marker of diabetes mellitus. Am J Dermatopathol.1997;19(5):540-4. [PubMed]

7. Snow SN, Reizner GT. Eccrine porocarcinoma of the face. J Am Acad Dermatol. 1992;27(2 Pt 2):306-11. PubMed [PubMed]

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